Win 7 Pro License on Home Primium Install

I currently have Vista Home Primium 32 installed on a laptop. I want to take advantage of the MS student discount but they only offer Windows 7 Professional. There is no upgrade path other than a clean install for Vista Home Primium to Win 7 Pro. If I do an upgrade to Windows 7 Home Primium 32 can I use my Pro license key?

Or can I do the upgrade to Win 7 Home Primium but do not activate and then immediately do another upgrade to my licensed Windows 7 Professional?

In a word, No

The key issued for the particular Version purchased is locked to that version.

Hope this helps,

Don