I don't think this has anything to do with VSS images.
http://msdn.microsoft.com/en-us/library/windows/desktop/bb891959(v=vs.85).aspx
"Applications that perform volume-level backups generally do so by copying the entire volume at the block level, so they cannot honor the FilesNotToBackup registry key at backup time. Instead, they wait until restore time to delete the files that were not to be backed up. In most cases, this is a reasonable strategy. However, in the case of Single Instance Storage files, the SIS Common Store files must not be deleted at restore time."
If Symantec decided to remove the files on the restore from DVD, that's a different issue.
