Vista Business/Ultimate for 70-620 Self-Study

How necessary is it to have Vista Business/Ultimate to study for the 70-620 exam?
I'm using the MS Press book via Techref. For some reason this book through Techref doesn't provide the disk image (where many other books do).
I have a real license for Home Premium. I know that I can't attach that version to a domain, but does this really matter in when studying for 70-620? I'd prefer to go with something that I have in-hand on a disk as opposed to download disk images for a trial, etc...
Thanks,
MS
I'm using the MS Press book via Techref. For some reason this book through Techref doesn't provide the disk image (where many other books do).
I have a real license for Home Premium. I know that I can't attach that version to a domain, but does this really matter in when studying for 70-620? I'd prefer to go with something that I have in-hand on a disk as opposed to download disk images for a trial, etc...
Thanks,
MS
Comments
Also, I believe you can install any version you want without entering a key and use it for 60 days.
Thanks dynamik. I've heard this also.
Sounds like Home Premium will work for my needs.
MS
http://news.softpedia.com/news/Microsoft-Offers-Official-Hacks-for-Vista-SP1-and-Windows-Server-2008-Free-Rides-78522.shtml
You may learn something!
That's what happens when I read the book!
I installed Ultimate under VMware and am going with a 30-day trial...I'm hoping to take the exam as soon as next Monday so I should be good.
MS
All the Vista media is the same, the key is the only thing that designates which version you have.