TFS Checkin Configuration - Query Support

The improvements that have been made recently to the TFS Version control plug in are awesome!  It's making the normally painful TFS easier to work with - thanks!

However, when I choose to configure the checkin parameters, I can't get the work items i need displayed (nothing displays - either I have too many results or it reports "unexpected property").  Is there anyway to modify/customize the list of queries that are provided on the "work items" tab?  Or could you explain where the list comes from in TFS?