Trying to interact with file menus

[7uxifer]

I'm trying to interact with a popup file menu, but I can't really figure out how.
These are windows menus, spawned by my SUT, so I can't use automation IDs.
I have a file browser with 2 panes ( tree on left, list on right), and a textbox and 2 buttons at bottom (cancel, open).
I need to at least:
click on several files, then click open
clickObject xpath=//Button[@text='Open'] works fine for open, but I can't figure out how to click on files.

I would also like to be able to enter text in the navigate bar at the top so I can go to remote folders, and/or click on folders in the tree.

any advice would be great, thanks