Undo Checkout has never worked

I have a question with Vault 1.2.2 Undo Checkout from the Visual Studio 2003 IDE.  Basically, no one on my team has ever gotten it to work.  It always seems to just do a "check in" with the changes that you made, defeating the whole purpose.  I even have a new member of the team who has a completely clean install (hasn't yet had time to monkey with settings) and still couldn't get "Undo. . " to work.  Any ideas?  We are probably just missing something.  Overall we love Vault!

 

Thanks,

Josh