Webrunner
It helped me, in the sense that I was reminded that you can't take a backup of a snapshot
I suggest you go to BOL (The link is in my previous post), which says you can backup a snapshot. True it is 3rd party software, but SQL 2005 contains built in specific capability to allow the 3rd party software to perform a back up of a snapshot.
So can a snapshot be backed up or not. Certainly not using SSMS or other SQL tools generally available to a DBA, but it can be backed up..