we may have been a tid bit too helpful to the Win 7 team by using the RC at present I too fell victim to that and now an attempt to save all files to disk and reinstall vista is being made to prepare for the actual "upgrade edition"
My thoughts are they could just put a flash screen up to insert your "valid product code" upon install because really its not an upgrade the Win 7 version is going to rip out Vista anyway. They could at least support the people who have supported them and their RC in attempt to run from Vista "the reason Win 7 is being pushed"
I dunno but they aint too bright at Microsoft