Great looking T there Joe! Since you've been welcomed to the site for a while let Welcome you to be a captain of the best two wheel machine in the world
I believe that STB mounted her's to the stock Triumph luggage rack.
Or you can go with one of these. http://wompusracks.com/triumph-rack.html I met the owner at a DQ one day in Gainesville, GA. Veteran and all around nice guy. The Ogre has one of these racks.
That's the same one I have on my touring, its not terribly complicated to fabricate mounts to put it directly onto the backrack with the passenger backrest removed. 2 tubes with the holes tapped out to accept the bolts when you remove the backrest, then you can still use the quick disconnect to take the pack off to service under the seat. Any local metal shop could make them cheap for you. I don't know what comes stock with the pack,I bought mine from a member, it has a plastic bottom, I have bolts through the pack, and have doubled up electrical conduit braces to go around the bars of the existing rack. This winter, I am going to change it over to a firm rubber with a different way of securing it, the galvanized braces seem to stretch after a couple months of vibration. PM me if you like, and I can send you pics of my existing one, but I will be posting when I do the final mods........that's what we do with our bitter winter up north.