[TxMt] Subversion and project files

I have read in older threads from the list about issues with subversion and project files lying outside of the root folder of the subversion project, but I am having difficulty getting the "Update Entire Project to Newest" to work. Specifically, that menu option never shows up, regardless of where I have my tmproj file in relation to the local svn files. Any idea what I'm doing wrong?

The Help file mentions that the folders need to be beneath TM_PROJECT_PATH and I can't find that environment variable anywhere. TextMate's Help mentions TM_PROJECT_DIRECTORY--is that what the SVN help file means? And if so, do I need to manually set it, or is it set when I have a saved tmproj open?