Upgrading Home Premium to Ultimate?

I bought the Vista Ultimate upgrade (not the anytime upgrade). Can I use it to upgrade my vista Home Premium to Ultimate? If I do will it wipe out my settings like when I upgraded from XP to Vista (on my 8600, not this 1730)? I don't really want to do a clean install. Also since this is a dual boot machine with XP on one drive and Vista on the other drive. So I really don't want to change that either.