EXchange mailboxes are empty
Restore to RSG can be as simple as clicking the Restore to RSG box in the restore popup. Exchange is finicky about one condition. The RSG has to be new, empty, and unmounted, and look exactly like the original storage group in terms of its database list. You can read about it in the NetBackup for Exchange admin guide. You have to take a version of the guide from before we dropped Exchange 2007 support (8.1?).
From its inception in NetBackup 6.5.2, Exchange GRT has not been an essential feature to protect your data. It can be such a huge time saver that it's a major inconvenience when it doesn't work for you. There has never been a case in these 11 years where a failed GRT browse indicated that the database backup itself was bad.
After re-reading your initial post, I see that you do see the mailboxes when browsing the image. Given that, neither bplist nor cat_convert will show you more, even for the databases that you can drill into. That's because the backup only catalogs to the mailbox level. The mailbox content is discovered by a "live browse" of the backup image.
You can go through logs to see why browsing into the mailboxes doesn't work for you, but that's probably not a fruitful path to pursue on such an old release. Also, consider that there were maintenance releases to 7.1 through 7.1.0.4. Some of these had to do with Exchange GRT, but in my memory they involved Exchange 2010.
An idea that occurs to me is that the database movement could be a hint. Make sure you are browsing a single backup image from either before or after the move. When you browse a set of images, NetBackup shows you the net state of the set as of the most recent image included. For example, if the selection includes images that span the move, the BAR GUI could show you the mailbox in the old database, but the live browse would look at the last image of the database, which does not include the mailbox.
