diff --git a/Classes/PHPExcel/Shared/TempFileTracker.php b/Classes/PHPExcel/Shared/TempFileTracker.php
new file mode 100644
index 000000000..6edf9fc9c
--- /dev/null
+++ b/Classes/PHPExcel/Shared/TempFileTracker.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * PHPExcel
+ *
+ * Copyright (c) 2006 - 2014 PHPExcel
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * @category   PHPExcel
+ * @package	PHPExcel_Shared_TempFileTracker
+ * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
+ * @license	http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt	LGPL
+ * @version	##VERSION##, ##DATE##
+ */
+
+/**
+ * PHPExcel_Shared_TempFileTracker
+ *
+ * @category   PHPExcel
+ * @package	PHPExcel_Shared_TempFileTracker
+ * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
+ */
+class PHPExcel_Shared_TempFileTracker
+{
+	/**
+	 * List of created temporary files
+	 *
+	 * @var array
+	 */
+	private $_files;
+
+	function __construct ()
+	{
+		$this->_files = array ();
+	}
+
+	function __destruct ()
+	{
+		$this->removeAllFiles ();
+	}
+
+	/**
+	 * Register a new temporary file.
+	 *
+	 * @param string $filename
+	 */
+	public function registerFile ($filename)
+	{
+		$this->_files[] = $filename;
+	}
+
+	/**
+	 * Generate a new temporary file name, and register it.
+	 *
+	 * @param string $prefix the new filename prefix.
+	 * @return string the new temporary filename.
+	 */
+	public function getNewFile ($prefix)
+	{
+		$filename = @tempnam (PHPExcel_Shared_File::sys_get_temp_dir(), $prefix);
+		$this->registerFile ($filename);
+		return $filename;
+	}
+
+	/**
+	 * Remove all the registered files.
+	 */
+	public function removeAllFiles ()
+	{
+		foreach ($this->_files as $file)
+			unlink ($file);
+		$this->_files = array ();
+	}
+}
+
+?>
diff --git a/Classes/PHPExcel/Shared/XMLWriter.php b/Classes/PHPExcel/Shared/XMLWriter.php
index beca51fc5..a69f11df7 100644
--- a/Classes/PHPExcel/Shared/XMLWriter.php
+++ b/Classes/PHPExcel/Shared/XMLWriter.php
@@ -42,36 +42,33 @@
  * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
  */
 class PHPExcel_Shared_XMLWriter extends XMLWriter {
-	/** Temporary storage method */
-	const STORAGE_MEMORY	= 1;
-	const STORAGE_DISK		= 2;
+	const FLUSH_FREQUENCY = 100;
 
 	/**
 	 * Temporary filename
 	 *
 	 * @var string
 	 */
-	private $_tempFileName = '';
+	private $_filename = '';
+
+	private $counter;
 
 	/**
 	 * Create a new PHPExcel_Shared_XMLWriter instance
 	 *
-	 * @param int		$pTemporaryStorage			Temporary storage location
-	 * @param string	$pTemporaryStorageFolder	Temporary storage folder
+	 * @param string	$filename	Temporary storage filename (empty to use memory)
 	 */
-	public function __construct($pTemporaryStorage = self::STORAGE_MEMORY, $pTemporaryStorageFolder = NULL) {
+	public function __construct($filename = NULL) {
 		// Open temporary storage
-		if ($pTemporaryStorage == self::STORAGE_MEMORY) {
+		if (!$filename) {
 			$this->openMemory();
 		} else {
-			// Create temporary filename
-			if ($pTemporaryStorageFolder === NULL)
-				$pTemporaryStorageFolder = PHPExcel_Shared_File::sys_get_temp_dir();
-			$this->_tempFileName = @tempnam($pTemporaryStorageFolder, 'xml');
+			$this->_filename = $filename;
 
 			// Open storage
-			if ($this->openUri($this->_tempFileName) === false) {
+			if ($this->openUri($this->_filename) === false) {
 				// Fallback to memory...
+				$this->_filename = '';
 				$this->openMemory();
 			}
 		}
@@ -80,16 +77,44 @@ public function __construct($pTemporaryStorage = self::STORAGE_MEMORY, $pTempora
 		if (DEBUGMODE_ENABLED) {
 			$this->setIndent(true);
 		}
+		$this->counter = self::FLUSH_FREQUENCY;
 	}
 
-	/**
-	 * Destructor
-	 */
-	public function __destruct() {
-		// Unlink temporary files
-		if ($this->_tempFileName != '') {
-			@unlink($this->_tempFileName);
-		}
+	public function flush($empty=true)
+	{
+		parent::flush($empty);
+		$this->counter = self::FLUSH_FREQUENCY;
+	}
+
+	private function flushIfNecessary()
+	{
+		if ($this->_filename == '')
+			return;
+
+		--$this->counter;
+		if ($this->counter <= 0)
+			$this->flush();
+	}
+
+	public function endElement()
+	{
+		$ret = parent::endElement();
+		$this->flushIfNecessary();
+		return $ret;
+	}
+
+	public function writeElement($name, $content=null)
+	{
+		$ret = parent::writeElement($name, $content);
+		$this->flushIfNecessary();
+		return $ret;
+	}
+
+	public function writeAttribute($name, $value)
+	{
+		$ret = parent::writeAttribute($name, $value);
+		$this->flushIfNecessary();
+		return $ret;
 	}
 
 	/**
@@ -98,14 +123,23 @@ public function __destruct() {
 	 * @return $data
 	 */
 	public function getData() {
-		if ($this->_tempFileName == '') {
+		if ($this->_filename == '') {
 			return $this->outputMemory(true);
 		} else {
 			$this->flush();
-			return file_get_contents($this->_tempFileName);
+			return file_get_contents($this->_filename);
 		}
 	}
 
+	/**
+	 * Get the temporary file name.
+	 *
+	 * @return filename;
+	 */
+	public function getFileName() {
+		return $this->_filename;
+	}
+
 	/**
 	 * Fallback method for writeRaw, introduced in PHP 5.2
 	 *
diff --git a/Classes/PHPExcel/Shared/ZipArchive.php b/Classes/PHPExcel/Shared/ZipArchive.php
index 9a801a841..00d120814 100644
--- a/Classes/PHPExcel/Shared/ZipArchive.php
+++ b/Classes/PHPExcel/Shared/ZipArchive.php
@@ -85,6 +85,30 @@ public function close()
 	{
 	}
 
+    /**
+     * Add a new file to the zip archive.
+     *
+     * @param	string	$filename		The path to the file to add to the zip archive
+     * @param	string	$localname		Directory/Name of the file to add to the zip archive
+     */
+    public function addFile($filename, $localname=null)
+    {
+        if (is_null ($localname))
+            $localname = $filename;
+
+        $filenameParts = pathinfo($localname);
+        copy($filename, $this->_tempDir.'/'.$filenameParts["basename"]);
+
+		$res = $this->_zip->add($this->_tempDir.'/'.$filenameParts["basename"],
+								PCLZIP_OPT_REMOVE_PATH, $this->_tempDir,
+								PCLZIP_OPT_ADD_PATH, $filenameParts["dirname"]
+							   );
+		if ($res == 0) {
+			throw new PHPExcel_Writer_Exception("Error zipping files : " . $this->_zip->errorInfo(true));
+		}
+
+		unlink($this->_tempDir.'/'.$filenameParts["basename"]);
+    }
 
     /**
 	 * Add a new file to the zip archive from a string of raw data.
diff --git a/Classes/PHPExcel/Writer/Excel2007.php b/Classes/PHPExcel/Writer/Excel2007.php
index 4cf14ac1c..fa470408d 100644
--- a/Classes/PHPExcel/Writer/Excel2007.php
+++ b/Classes/PHPExcel/Writer/Excel2007.php
@@ -123,6 +123,13 @@ class PHPExcel_Writer_Excel2007 extends PHPExcel_Writer_Abstract implements PHPE
 	 */
 	private $_drawingHashTable;
 
+	/**
+	 * Private temporary file list.
+	 *
+	 * @var PHPExcel_Shared_TempFileTracker
+	 */
+	private $_tempFileTracker;
+
     /**
      * Create a new PHPExcel_Writer_Excel2007
      *
@@ -163,6 +170,8 @@ public function __construct(PHPExcel $pPHPExcel = null)
 		foreach ($hashTablesArray as $tableName) {
 			$this->$tableName 	= new PHPExcel_HashTable();
 		}
+
+		$this->_tempFileTracker = new PHPExcel_Shared_TempFileTracker();
     }
 
 	/**
@@ -243,7 +252,7 @@ public function save($pFilename = null)
 			}
 
 			// Add [Content_Types].xml to ZIP file
-			$objZip->addFromString('[Content_Types].xml', 			$this->getWriterPart('ContentTypes')->writeContentTypes($this->_spreadSheet, $this->_includeCharts));
+			$this->getWriterPart('ContentTypes')->addContentTypesToZip($this->_spreadSheet, $objZip, '[Content_Types].xml', $this->_includeCharts);
 
 			//if hasMacros, add the vbaProject.bin file, Certificate file(if exists)
 			if($this->_spreadSheet->hasMacros()){
@@ -253,8 +262,7 @@ public function save($pFilename = null)
 					if($this->_spreadSheet->hasMacrosCertificate()){//signed macros ?
 						// Yes : add the certificate file and the related rels file
 						$objZip->addFromString('xl/vbaProjectSignature.bin', $this->_spreadSheet->getMacrosCertificate());
-						$objZip->addFromString('xl/_rels/vbaProject.bin.rels',
-							$this->getWriterPart('RelsVBA')->writeVBARelationships($this->_spreadSheet));
+						$this->getWriterPart('RelsVBA')->addVBARelationshipsToZip($this->_spreadSheet, $objZip, 'xl/_rels/vbaProject.bin.rels');
 					}
 				}
 			}
@@ -269,44 +277,44 @@ public function save($pFilename = null)
 						$objZip->addFromString($tmpRootPath.$aPath, $aContent);
 					}
 					//the rels for files
-					$objZip->addFromString($tmpRootPath.'_rels/'.basename($tmpRibbonTarget).'.rels',
-						$this->getWriterPart('RelsRibbonObjects')->writeRibbonRelationships($this->_spreadSheet));
+					$this->getWriterPart('RelsRibbonObjects')->addRibbonRelationshipsToZip($this->_spreadSheet, $objZip,
+																						   $tmpRootPath.'_rels/'.basename($tmpRibbonTarget).'.rels');
 				}
 			}
 			
 			// Add relationships to ZIP file
-			$objZip->addFromString('_rels/.rels', 					$this->getWriterPart('Rels')->writeRelationships($this->_spreadSheet));
-			$objZip->addFromString('xl/_rels/workbook.xml.rels', 	$this->getWriterPart('Rels')->writeWorkbookRelationships($this->_spreadSheet));
+			$this->getWriterPart('Rels')->addRelationshipsToZip($this->_spreadSheet, $objZip, '_rels/.rels');
+			$this->getWriterPart('Rels')->addWorkbookRelationshipsToZip($this->_spreadSheet, $objZip, 'xl/_rels/workbook.xml.rels');
 
 			// Add document properties to ZIP file
-			$objZip->addFromString('docProps/app.xml', 				$this->getWriterPart('DocProps')->writeDocPropsApp($this->_spreadSheet));
-			$objZip->addFromString('docProps/core.xml', 			$this->getWriterPart('DocProps')->writeDocPropsCore($this->_spreadSheet));
-			$customPropertiesPart = $this->getWriterPart('DocProps')->writeDocPropsCustom($this->_spreadSheet);
-			if ($customPropertiesPart !== NULL) {
-				$objZip->addFromString('docProps/custom.xml', 		$customPropertiesPart);
-			}
+			$this->getWriterPart('DocProps')->addDocPropsAppToZip($this->_spreadSheet, $objZip, 'docProps/app.xml');
+			$this->getWriterPart('DocPRops')->addDocPropsCoreToZip($this->_spreadSheet, $objZip, 'docProps/core.xml');
+			$this->getWriterPart('DocProps')->addDocPropsCustomToZip($this->_spreadSheet, $objZip, 'docProps/custom.xml');
 
 			// Add theme to ZIP file
-			$objZip->addFromString('xl/theme/theme1.xml', 			$this->getWriterPart('Theme')->writeTheme($this->_spreadSheet));
+			$this->getWriterPart('Theme')->addThemeToZip($this->_spreadSheet, $objZip, 'xl/theme/theme1.xml');
 
 			// Add string table to ZIP file
-			$objZip->addFromString('xl/sharedStrings.xml', 			$this->getWriterPart('StringTable')->writeStringTable($this->_stringTable));
+			$this->getWriterPart('StringTable')->addStringTableToZip($this->_stringTable, $objZip, 'xl/sharedStrings.xml');
 
 			// Add styles to ZIP file
-			$objZip->addFromString('xl/styles.xml', 				$this->getWriterPart('Style')->writeStyles($this->_spreadSheet));
+			$this->getWriterPart('Style')->addStylesToZip($this->_spreadSheet, $objZip, 'xl/styles.xml');
 
 			// Add workbook to ZIP file
-			$objZip->addFromString('xl/workbook.xml', 				$this->getWriterPart('Workbook')->writeWorkbook($this->_spreadSheet, $this->_preCalculateFormulas));
+			$this->getWriterPart('Workbook')->addWorkbookToZip($this->_spreadSheet, $objZip, 'xl/workbook.xml', $this->_preCalculateFormulas);
 
 			$chartCount = 0;
 			// Add worksheets
 			for ($i = 0; $i < $this->_spreadSheet->getSheetCount(); ++$i) {
-				$objZip->addFromString('xl/worksheets/sheet' . ($i + 1) . '.xml', $this->getWriterPart('Worksheet')->writeWorksheet($this->_spreadSheet->getSheet($i), $this->_stringTable, $this->_includeCharts));
+				$currentSheet = $this->_spreadSheet->getSheet($i);
+
+				$this->getWriterPart('Worksheet')->addWorksheetToZip($currentSheet, $objZip, 'xl/worksheets/sheet'.($i+1).'.xml',
+				                                                     $this->_stringTable, $this->_includeCharts);
 				if ($this->_includeCharts) {
-					$charts = $this->_spreadSheet->getSheet($i)->getChartCollection();
+					$charts = $currentSheet->getChartCollection();
 					if (count($charts) > 0) {
 						foreach($charts as $chart) {
-							$objZip->addFromString('xl/charts/chart' . ($chartCount + 1) . '.xml', $this->getWriterPart('Chart')->writeChart($chart));
+							$this->getWriterPart('Chart')->addChartToZip($chart, $objZip, 'xl/charts/chart' . ($chartCount + 1) . '.xml');
 							$chartCount++;
 						}
 					}
@@ -316,53 +324,58 @@ public function save($pFilename = null)
 			$chartRef1 = $chartRef2 = 0;
 			// Add worksheet relationships (drawings, ...)
 			for ($i = 0; $i < $this->_spreadSheet->getSheetCount(); ++$i) {
+				$currentSheet = $this->_spreadSheet->getSheet($i);
 
 				// Add relationships
-				$objZip->addFromString('xl/worksheets/_rels/sheet' . ($i + 1) . '.xml.rels', 	$this->getWriterPart('Rels')->writeWorksheetRelationships($this->_spreadSheet->getSheet($i), ($i + 1), $this->_includeCharts));
+				$this->getWriterPart('Rels')->addWorksheetRelationshipsToZip($currentSheet, $objZip,
+																			 'xl/worksheets/_rels/sheet' . ($i + 1) . '.xml.rels', 
+																			 ($i + 1), $this->_includeCharts);
 
-				$drawings = $this->_spreadSheet->getSheet($i)->getDrawingCollection();
+				$drawings = $currentSheet->getDrawingCollection();
 				$drawingCount = count($drawings);
 				if ($this->_includeCharts) {
-					$chartCount = $this->_spreadSheet->getSheet($i)->getChartCount();
+					$chartCount = $currentSheet->getChartCount();
 				}
 
 				// Add drawing and image relationship parts
 				if (($drawingCount > 0) || ($chartCount > 0)) {
 					// Drawing relationships
-					$objZip->addFromString('xl/drawings/_rels/drawing' . ($i + 1) . '.xml.rels', $this->getWriterPart('Rels')->writeDrawingRelationships($this->_spreadSheet->getSheet($i),$chartRef1, $this->_includeCharts));
+					$this->getWriterPart('Rels')->addDrawingRelationshipsToZip($currentSheet, $chartRef1, $objZip,
+																			   'xl/drawings/_rels/drawing' . ($i + 1) . '.xml.rels', $this->_includeCharts);
 
 					// Drawings
-					$objZip->addFromString('xl/drawings/drawing' . ($i + 1) . '.xml', $this->getWriterPart('Drawing')->writeDrawings($this->_spreadSheet->getSheet($i),$chartRef2,$this->_includeCharts));
+					$this->getWriterPart('Drawing')->addDrawingsToZip($currentSheet, $chartRef2, $objZip,
+																	  'xl/drawings/drawing' . ($i + 1) . '.xml', $this->_includeCharts);
 				}
 
 				// Add comment relationship parts
-				if (count($this->_spreadSheet->getSheet($i)->getComments()) > 0) {
+				if (count($currentSheet->getComments()) > 0) {
 					// VML Comments
-					$objZip->addFromString('xl/drawings/vmlDrawing' . ($i + 1) . '.vml', $this->getWriterPart('Comments')->writeVMLComments($this->_spreadSheet->getSheet($i)));
+					$this->getWriterPart('Comments')->addVMLCommentsToZip($currentSheet, $objZip, 'xl/drawings/vmlDrawing' . ($i + 1) . '.vml');
 
 					// Comments
-					$objZip->addFromString('xl/comments' . ($i + 1) . '.xml', $this->getWriterPart('Comments')->writeComments($this->_spreadSheet->getSheet($i)));
+					$this->getWriterPart('Comments')->addCommentsToZip($currentSheet, $objZip, 'xl/comments' . ($i + 1) . '.xml');
 				}
 
 				// Add header/footer relationship parts
-				if (count($this->_spreadSheet->getSheet($i)->getHeaderFooter()->getImages()) > 0) {
+				if (count($currentSheet->getHeaderFooter()->getImages()) > 0) {
 					// VML Drawings
-					$objZip->addFromString('xl/drawings/vmlDrawingHF' . ($i + 1) . '.vml', $this->getWriterPart('Drawing')->writeVMLHeaderFooterImages($this->_spreadSheet->getSheet($i)));
+					$this->getWriterPart('Drawing')->addVMLHeaderFooterImagesToZip($currentSheet, $objZip, 'xl/drawings/vmlDrawingHF' . ($i + 1) . '.vml');
 
 					// VML Drawing relationships
-					$objZip->addFromString('xl/drawings/_rels/vmlDrawingHF' . ($i + 1) . '.vml.rels', $this->getWriterPart('Rels')->writeHeaderFooterDrawingRelationships($this->_spreadSheet->getSheet($i)));
+					$this->getWriterPart('Rels')->addHeaderFooterDrawingRelationshipsToZip($currentSheet, $objZip, 'xl/drawings/_rels/vmlDrawingHF' . ($i + 1) . '.vml.rels');
 
 					// Media
-					foreach ($this->_spreadSheet->getSheet($i)->getHeaderFooter()->getImages() as $image) {
-						$objZip->addFromString('xl/media/' . $image->getIndexedFilename(), file_get_contents($image->getPath()));
+					foreach ($currentSheet->getHeaderFooter()->getImages() as $image) {
+						$objZip->addFile($image->getPath(), 'xl/media/' . $image->getIndexedFilename());
 					}
 				}
 			}
 
 			// Add media
 			for ($i = 0; $i < $this->getDrawingHashTable()->count(); ++$i) {
+				$imageName = str_replace(' ', '_', $this->getDrawingHashTable()->getByIndex($i)->getIndexedFilename());
 				if ($this->getDrawingHashTable()->getByIndex($i) instanceof PHPExcel_Worksheet_Drawing) {
-					$imageContents = null;
 					$imagePath = $this->getDrawingHashTable()->getByIndex($i)->getPath();
 					if (strpos($imagePath, 'zip://') !== false) {
 						$imagePath = substr($imagePath, 6);
@@ -373,11 +386,11 @@ public function save($pFilename = null)
 						$imageContents = $imageZip->getFromName($imagePathSplitted[1]);
 						$imageZip->close();
 						unset($imageZip);
+						$objzip->addFromString('xl/media/' . $imagename, $imagecontents);
 					} else {
-						$imageContents = file_get_contents($imagePath);
+						$objZip->addFile($imagePath, 'xl/media/' . $imageName);
 					}
 
-					$objZip->addFromString('xl/media/' . str_replace(' ', '_', $this->getDrawingHashTable()->getByIndex($i)->getIndexedFilename()), $imageContents);
 				} else if ($this->getDrawingHashTable()->getByIndex($i) instanceof PHPExcel_Worksheet_MemoryDrawing) {
 					ob_start();
 					call_user_func(
@@ -387,7 +400,7 @@ public function save($pFilename = null)
 					$imageContents = ob_get_contents();
 					ob_end_clean();
 
-					$objZip->addFromString('xl/media/' . str_replace(' ', '_', $this->getDrawingHashTable()->getByIndex($i)->getIndexedFilename()), $imageContents);
+					$objZip->addFromString('xl/media/' . $imageName, $imageContents);
 				}
 			}
 
@@ -396,12 +409,14 @@ public function save($pFilename = null)
 
 			// Close file
 			if ($objZip->close() === false) {
+				$this->_tempFileTracker->removeAllFiles ();
 				throw new PHPExcel_Writer_Exception("Could not close zip file $pFilename.");
 			}
 
 			// If a temporary file was used, copy it to the correct file stream
 			if ($originalFilename != $pFilename) {
 				if (copy($pFilename, $originalFilename) === false) {
+					$this->_tempFileTracker->removeAllFiles ();
 					throw new PHPExcel_Writer_Exception("Could not copy temporary zip file $pFilename to $originalFilename.");
 				}
 				@unlink($pFilename);
@@ -409,6 +424,8 @@ public function save($pFilename = null)
 		} else {
 			throw new PHPExcel_Writer_Exception("PHPExcel object unassigned.");
 		}
+
+		$this->_tempFileTracker->removeAllFiles ();
 	}
 
 	/**
@@ -529,4 +546,12 @@ public function setOffice2003Compatibility($pValue = false) {
     	return $this;
     }
 
+    /**
+     * Get the temporary file tracker.
+     *
+     * @return PHPExcel_Shared_TempFileTracker
+     */
+    public function getTempFileTracker() {
+        return $this->_tempFileTracker;
+    }
 }
diff --git a/Classes/PHPExcel/Writer/Excel2007/Chart.php b/Classes/PHPExcel/Writer/Excel2007/Chart.php
index 0b686b912..59c53f5c0 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Chart.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Chart.php
@@ -39,18 +39,15 @@ class PHPExcel_Writer_Excel2007_Chart extends PHPExcel_Writer_Excel2007_WriterPa
 	 * Write charts to XML format
 	 *
 	 * @param 	PHPExcel_Chart				$pChart
-	 * @return 	string 						XML Output
+	 * @param	ZipArchive					$objZip
+	 * @param	string						$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeChart(PHPExcel_Chart $pChart = null)
+	public function addChartToZip(PHPExcel_Chart $pChart, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
+
 		//	Ensure that data series values are up-to-date before we save
 		$pChart->refresh();
 
@@ -111,8 +108,8 @@ public function writeChart(PHPExcel_Chart $pChart = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/Comments.php b/Classes/PHPExcel/Writer/Excel2007/Comments.php
index dc809fa8e..555cea731 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Comments.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Comments.php
@@ -38,19 +38,15 @@ class PHPExcel_Writer_Excel2007_Comments extends PHPExcel_Writer_Excel2007_Write
 	/**
 	 * Write comments to XML format
 	 *
-	 * @param 	PHPExcel_Worksheet				$pWorksheet
-	 * @return 	string 								XML Output
+	 * @param 	PHPExcel_Worksheet	$pWorksheet
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeComments(PHPExcel_Worksheet $pWorksheet = null)
+	public function addCommentsToZip(PHPExcel_Worksheet $pWorksheet, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -87,8 +83,8 @@ public function writeComments(PHPExcel_Worksheet $pWorksheet = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
@@ -118,19 +114,15 @@ public function _writeComment(PHPExcel_Shared_XMLWriter $objWriter = null, $pCel
 	/**
 	 * Write VML comments to XML format
 	 *
-	 * @param 	PHPExcel_Worksheet				$pWorksheet
-	 * @return 	string 								XML Output
+	 * @param 	PHPExcel_Worksheet	$pWorksheet
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeVMLComments(PHPExcel_Worksheet $pWorksheet = null)
+	public function writeVMLComments(PHPExcel_Worksheet $pWorksheet, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -183,8 +175,8 @@ public function writeVMLComments(PHPExcel_Worksheet $pWorksheet = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/ContentTypes.php b/Classes/PHPExcel/Writer/Excel2007/ContentTypes.php
index 557853654..9cc6f5d86 100644
--- a/Classes/PHPExcel/Writer/Excel2007/ContentTypes.php
+++ b/Classes/PHPExcel/Writer/Excel2007/ContentTypes.php
@@ -39,19 +39,15 @@ class PHPExcel_Writer_Excel2007_ContentTypes extends PHPExcel_Writer_Excel2007_W
 	 * Write content types to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @param	boolean		$includeCharts	Flag indicating if we should include drawing details for charts
-	 * @return 	string 						XML Output
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeContentTypes(PHPExcel $pPHPExcel = null, $includeCharts = FALSE)
+	public function addContentTypesToZip(PHPExcel $pPHPExcel, $objZip, $filename, $includeCharts = FALSE)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -222,8 +218,8 @@ public function writeContentTypes(PHPExcel $pPHPExcel = null, $includeCharts = F
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/DocProps.php b/Classes/PHPExcel/Writer/Excel2007/DocProps.php
index f8821379c..ce52ff88d 100644
--- a/Classes/PHPExcel/Writer/Excel2007/DocProps.php
+++ b/Classes/PHPExcel/Writer/Excel2007/DocProps.php
@@ -39,18 +39,14 @@ class PHPExcel_Writer_Excel2007_DocProps extends PHPExcel_Writer_Excel2007_Write
 	 * Write docProps/app.xml to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeDocPropsApp(PHPExcel $pPHPExcel = null)
+	public function addDocPropsAppToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -128,26 +124,22 @@ public function writeDocPropsApp(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
 	 * Write docProps/core.xml to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeDocPropsCore(PHPExcel $pPHPExcel = null)
+	public function addDocPropsCoreToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -195,18 +187,19 @@ public function writeDocPropsCore(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
 	 * Write docProps/custom.xml to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeDocPropsCustom(PHPExcel $pPHPExcel = null)
+	public function addDocPropsCustomToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		$customPropertyList = $pPHPExcel->getProperties()->getCustomProperties();
 		if (empty($customPropertyList)) {
@@ -214,12 +207,7 @@ public function writeDocPropsCustom(PHPExcel $pPHPExcel = null)
 		}
 
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -265,8 +253,8 @@ public function writeDocPropsCustom(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 }
diff --git a/Classes/PHPExcel/Writer/Excel2007/Drawing.php b/Classes/PHPExcel/Writer/Excel2007/Drawing.php
index 1cf971ed4..5afe28498 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Drawing.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Drawing.php
@@ -40,19 +40,15 @@ class PHPExcel_Writer_Excel2007_Drawing extends PHPExcel_Writer_Excel2007_Writer
 	 *
 	 * @param 	PHPExcel_Worksheet	$pWorksheet
 	 * @param	int					&$chartRef		Chart ID
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @param	boolean				$includeCharts	Flag indicating if we should include drawing details for charts
-	 * @return 	string 				XML Output
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeDrawings(PHPExcel_Worksheet $pWorksheet = null, &$chartRef, $includeCharts = FALSE)
+	public function addDrawingsToZip(PHPExcel_Worksheet $pWorksheet, &$chartRef, $objZip, $filename, $includeCharts = FALSE)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -85,8 +81,8 @@ public function writeDrawings(PHPExcel_Worksheet $pWorksheet = null, &$chartRef,
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
@@ -382,19 +378,15 @@ public function _writeDrawing(PHPExcel_Shared_XMLWriter $objWriter = null, PHPEx
 	/**
 	 * Write VML header/footer images to XML format
 	 *
-	 * @param 	PHPExcel_Worksheet				$pWorksheet
-	 * @return 	string 								XML Output
+	 * @param 	PHPExcel_Worksheet	$pWorksheet
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeVMLHeaderFooterImages(PHPExcel_Worksheet $pWorksheet = null)
+	public function addVMLHeaderFooterImagesToZip(PHPExcel_Worksheet $pWorksheet, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -522,8 +514,8 @@ public function writeVMLHeaderFooterImages(PHPExcel_Worksheet $pWorksheet = null
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/Rels.php b/Classes/PHPExcel/Writer/Excel2007/Rels.php
index a7d36c0a9..036c9d8f2 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Rels.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Rels.php
@@ -39,18 +39,14 @@ class PHPExcel_Writer_Excel2007_Rels extends PHPExcel_Writer_Excel2007_WriterPar
 	 * Write relationships to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeRelationships(PHPExcel $pPHPExcel = null)
+	public function addRelationshipsToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -106,26 +102,22 @@ public function writeRelationships(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
 	 * Write workbook relationships to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeWorkbookRelationships(PHPExcel $pPHPExcel = null)
+	public function addWorkbookRelationshipsToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -182,8 +174,8 @@ public function writeWorkbookRelationships(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
@@ -194,20 +186,16 @@ public function writeWorkbookRelationships(PHPExcel $pPHPExcel = null)
 	 *  rId_hyperlink_x 	- Hyperlinks
 	 *
 	 * @param 	PHPExcel_Worksheet	$pWorksheet
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @param 	int					$pWorksheetId
 	 * @param	boolean				$includeCharts	Flag indicating if we should write charts
-	 * @return 	string 				XML Output
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeWorksheetRelationships(PHPExcel_Worksheet $pWorksheet = null, $pWorksheetId = 1, $includeCharts = FALSE)
+	public function addWorksheetRelationshipsToZip(PHPExcel_Worksheet $pWorksheet, $objZip, $filename, $pWorksheetId = 1, $includeCharts = FALSE)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -295,8 +283,8 @@ public function writeWorksheetRelationships(PHPExcel_Worksheet $pWorksheet = nul
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
@@ -304,19 +292,15 @@ public function writeWorksheetRelationships(PHPExcel_Worksheet $pWorksheet = nul
 	 *
 	 * @param 	PHPExcel_Worksheet	$pWorksheet
 	 * @param	int					&$chartRef		Chart ID
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @param	boolean				$includeCharts	Flag indicating if we should write charts
-	 * @return 	string 				XML Output
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeDrawingRelationships(PHPExcel_Worksheet $pWorksheet = null, &$chartRef, $includeCharts = FALSE)
+	public function addDrawingRelationshipsToZip(PHPExcel_Worksheet $pWorksheet = null, &$chartRef, $objZip, $filename, $includeCharts = FALSE)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -361,26 +345,22 @@ public function writeDrawingRelationships(PHPExcel_Worksheet $pWorksheet = null,
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
 	 * Write header/footer drawing relationships to XML format
 	 *
-	 * @param 	PHPExcel_Worksheet			$pWorksheet
-	 * @return 	string 						XML Output
+	 * @param 	PHPExcel_Worksheet	$pWorksheet
+	 * @param	ZipArchive			$objZip
+	 * @param	string				$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeHeaderFooterDrawingRelationships(PHPExcel_Worksheet $pWorksheet = null)
+	public function addHeaderFooterDrawingRelationshipsToZip(PHPExcel_Worksheet $pWorksheet, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -402,8 +382,8 @@ public function writeHeaderFooterDrawingRelationships(PHPExcel_Worksheet $pWorks
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/RelsRibbon.php b/Classes/PHPExcel/Writer/Excel2007/RelsRibbon.php
index 615f2cbd9..fb55c445d 100644
--- a/Classes/PHPExcel/Writer/Excel2007/RelsRibbon.php
+++ b/Classes/PHPExcel/Writer/Excel2007/RelsRibbon.php
@@ -39,17 +39,13 @@ class PHPExcel_Writer_Excel2007_RelsRibbon extends PHPExcel_Writer_Excel2007_Wri
 	 * Write relationships for additional objects of custom UI (ribbon)
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeRibbonRelationships(PHPExcel $pPHPExcel = null){
+	public function addRibbonRelationshipsToZip(PHPExcel $pPHPExcel, $objZip, $filename) {
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -69,9 +65,8 @@ public function writeRibbonRelationships(PHPExcel $pPHPExcel = null){
 		}
 		$objWriter->endElement();//Relationships
 
-		// Return
-		return $objWriter->getData();
-
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 }
diff --git a/Classes/PHPExcel/Writer/Excel2007/RelsVBA.php b/Classes/PHPExcel/Writer/Excel2007/RelsVBA.php
index 3f87d81f2..b3d21e035 100644
--- a/Classes/PHPExcel/Writer/Excel2007/RelsVBA.php
+++ b/Classes/PHPExcel/Writer/Excel2007/RelsVBA.php
@@ -39,17 +39,13 @@ class PHPExcel_Writer_Excel2007_RelsVBA extends PHPExcel_Writer_Excel2007_Writer
 	 * Write relationships for a signed VBA Project
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeVBARelationships(PHPExcel $pPHPExcel = null){
+	public function addVBARelationshipsToZip(PHPExcel $pPHPExcel, $objZip, $filename) {
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -64,9 +60,8 @@ public function writeVBARelationships(PHPExcel $pPHPExcel = null){
 		$objWriter->endElement();//Relationship
 		$objWriter->endElement();//Relationships
 
-		// Return
-		return $objWriter->getData();
-
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 }
diff --git a/Classes/PHPExcel/Writer/Excel2007/StringTable.php b/Classes/PHPExcel/Writer/Excel2007/StringTable.php
index e8ca1c5a5..abd4d9ae6 100644
--- a/Classes/PHPExcel/Writer/Excel2007/StringTable.php
+++ b/Classes/PHPExcel/Writer/Excel2007/StringTable.php
@@ -89,19 +89,15 @@ public function createStringTable($pSheet = null, $pExistingTable = null)
 	 * Write string table to XML format
 	 *
 	 * @param 	string[] 	$pStringTable
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeStringTable($pStringTable = null)
+	public function addStringTableToZip($pStringTable, $objZip, $filename)
 	{
 		if ($pStringTable !== NULL) {
 			// Create XML writer
-			$objWriter = null;
-			if ($this->getParentWriter()->getUseDiskCaching()) {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-			} else {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-			}
+			$objWriter = $this->createXMLWriter();
 
 			// XML header
 			$objWriter->startDocument('1.0','UTF-8','yes');
@@ -132,8 +128,8 @@ public function writeStringTable($pStringTable = null)
 
 			$objWriter->endElement();
 
-			// Return
-			return $objWriter->getData();
+			// Add the generated file to the Zip file.
+			$this->addXMLToZip($objWriter, $objZip, $filename);
 		} else {
 			throw new PHPExcel_Writer_Exception("Invalid string table array passed.");
 		}
diff --git a/Classes/PHPExcel/Writer/Excel2007/Style.php b/Classes/PHPExcel/Writer/Excel2007/Style.php
index 9857043b8..8ff3c99ae 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Style.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Style.php
@@ -39,18 +39,14 @@ class PHPExcel_Writer_Excel2007_Style extends PHPExcel_Writer_Excel2007_WriterPa
 	 * Write styles to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeStyles(PHPExcel $pPHPExcel = null)
+	public function addStylesToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -161,8 +157,8 @@ public function writeStyles(PHPExcel $pPHPExcel = null)
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/Theme.php b/Classes/PHPExcel/Writer/Excel2007/Theme.php
index c67b94816..a77e8ce10 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Theme.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Theme.php
@@ -133,18 +133,14 @@ class PHPExcel_Writer_Excel2007_Theme extends PHPExcel_Writer_Excel2007_WriterPa
 	 * Write theme to XML format
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
-	 * @return 	string 		XML Output
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @throws 	PHPExcel_Writer_Exception
 	 */
-	public function writeTheme(PHPExcel $pPHPExcel = null)
+	public function addThemeToZip(PHPExcel $pPHPExcel, $objZip, $filename)
 	{
 			// Create XML writer
-			$objWriter = null;
-			if ($this->getParentWriter()->getUseDiskCaching()) {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-			} else {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-			}
+			$objWriter = $this->createXMLWriter();
 
 			// XML header
 			$objWriter->startDocument('1.0','UTF-8','yes');
@@ -809,8 +805,8 @@ public function writeTheme(PHPExcel $pPHPExcel = null)
 
 			$objWriter->endElement();
 
-			// Return
-			return $objWriter->getData();
+			// Add the generated file to the Zip file.
+			$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/Workbook.php b/Classes/PHPExcel/Writer/Excel2007/Workbook.php
index f30929476..940c550c6 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Workbook.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Workbook.php
@@ -36,22 +36,18 @@
 class PHPExcel_Writer_Excel2007_Workbook extends PHPExcel_Writer_Excel2007_WriterPart
 {
 	/**
-	 * Write workbook to XML format
+	 * Write workbook to XML format into the ZIP file.
 	 *
 	 * @param 	PHPExcel	$pPHPExcel
+	 * @param	ZipArchive	$objZip
+	 * @param	string		$filename
 	 * @param	boolean		$recalcRequired	Indicate whether formulas should be recalculated before writing
-	 * @return 	string 		XML Output
-	 * @throws 	PHPExcel_Writer_Exception
+	 * @throws	PHPExcel_Writer_Exception
 	 */
-	public function writeWorkbook(PHPExcel $pPHPExcel = null, $recalcRequired = FALSE)
+	public function addWorkbookToZip(PHPExcel $pPHPExcel, $objZip, $filename, $recalcRequired = FALSE)
 	{
 		// Create XML writer
-		$objWriter = null;
-		if ($this->getParentWriter()->getUseDiskCaching()) {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-		} else {
-			$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-		}
+		$objWriter = $this->createXMLWriter();
 
 		// XML header
 		$objWriter->startDocument('1.0','UTF-8','yes');
@@ -87,8 +83,8 @@ public function writeWorkbook(PHPExcel $pPHPExcel = null, $recalcRequired = FALS
 
 		$objWriter->endElement();
 
-		// Return
-		return $objWriter->getData();
+		// Add the generated file to the Zip file.
+		$this->addXMLToZip($objWriter, $objZip, $filename);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/Excel2007/Worksheet.php b/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
index 760581647..44dae0622 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
@@ -36,24 +36,20 @@
 class PHPExcel_Writer_Excel2007_Worksheet extends PHPExcel_Writer_Excel2007_WriterPart
 {
 	/**
-	 * Write worksheet to XML format
+	 * Write worksheet to XML format into the ZIP file.
 	 *
 	 * @param	PHPExcel_Worksheet		$pSheet
+	 * @param	ZipArchive				$objZip
+	 * @param	string					$filename
 	 * @param	string[]				$pStringTable
 	 * @param	boolean					$includeCharts	Flag indicating if we should write charts
-	 * @return	string					XML Output
 	 * @throws	PHPExcel_Writer_Exception
 	 */
-	public function writeWorksheet($pSheet = null, $pStringTable = null, $includeCharts = FALSE)
+	public function addWorksheetToZip($pSheet, $objZip, $filename, $pStringTable = null, $includeCharts = FALSE)
 	{
 		if (!is_null($pSheet)) {
 			// Create XML writer
-			$objWriter = null;
-			if ($this->getParentWriter()->getUseDiskCaching()) {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
-			} else {
-				$objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
-			}
+			$objWriter = $this->createXMLWriter();
 
 			// XML header
 			$objWriter->startDocument('1.0','UTF-8','yes');
@@ -129,8 +125,8 @@ public function writeWorksheet($pSheet = null, $pStringTable = null, $includeCha
 
 			$objWriter->endElement();
 
-			// Return
-			return $objWriter->getData();
+			// Add the generated file to the Zip file.
+			$this->addXMLToZip($objWriter, $objZip, $filename);
 		} else {
 			throw new PHPExcel_Writer_Exception("Invalid PHPExcel_Worksheet object passed.");
 		}
diff --git a/Classes/PHPExcel/Writer/Excel2007/WriterPart.php b/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
index 68b1124fd..52e143ac6 100644
--- a/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
+++ b/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
@@ -78,4 +78,24 @@ public function __construct(PHPExcel_Writer_IWriter $pWriter = null) {
 		}
 	}
 
+	protected function createXMLWriter() {
+		if ($this->getParentWriter()->getUseDiskCaching()) {
+			$filename = $this->getParentWriter()->getTempFileTracker()->getNewFile('xmlw');
+			return new PHPExcel_Shared_XMLWriter($filename);
+		} else {
+			return new PHPExcel_Shared_XMLWriter(NULL);
+		}
+	}
+
+	protected function addXMLToZip($objWriter, $objZip, $filename) {
+		// Add the generated file to the Zip file.
+		$tempFileName = $objWriter->getFileName();
+
+		if ($tempFileName) {
+			$objZip->addFile($tempFileName, $filename);
+		}
+		else {
+			$objZip->addFromString($filename, $objWriter->getData());
+		}
+	}
 }