If you're fortunate enough to have access to regular builds of Vista and you're using ASI, you may have noticed a change to the SKU parameter in Vista. The change went in around build 5212. Unfortunately that change makes it impossible to deploy current builds of Vista using ASI. Beta 1 builds still work, of course. This has been fixed in ASI, but it will take a while for the fix to work its way through all of our code branches. As soon as I know when we'll be releasing the fixes publiclly I'll post that informaiton here.
As a side note, I became aware of this when visiting one of our TAP partners. Internally the ASI team managed this seamlessly for us so I was not aware of the issue until I went out and talked to one of our customers. If you're in our TAP program, and you're actively using these tools, thanks! Please let me know what issues you're running into so we can address them for you.