Windows 8 Upgrade question

Hello MS Tribe readers,

I bought the MS Windows 8 Pro Pack upgrade (with the free media center add-on) from Best Buy (Canada).

My question is, can I upgrade Windows 8 Release Preview with this? Or does it have to be another version?

Any insight would be great, if I can't I'm going to take it back and do it through the Windows Upgrade Assistant as I did it for my friend and that worked but I wanted the Media Center add-on.

Thanks!