The modification was EASY. I'm surprised this isn't a well known thing. Seems that the rear fender width of the HDs is veddy close to the width of our rides. The hardest thing to do was to cut down the length of the mounting bracket. The HD bracket was too long - front to back - and I cut approx. 3 inches off the back so it's shape would "ergometrically flow" and blend in with the "chi" of my Speedy. Really, it's a "Feng Shui" kind of thing, if you know what I mean. Then I lined up the front mounting bolt of the brackets with the middle rear fender bolt of my speedy and marked the rear fender bolt location on the bracket. Then I drilled the H-E-Double-hockey-sticks out of that bracket so's I could mount it between the fender and the chrome strip on my bike. I then dry-fitted the brackets and set the sissy bar up to them to see what type of moves I needed to do next. Once I was 67% sure, I proceeded to set the brackets in my bench vise and bend the beejesus out of them (and the sissy bar) until they fit.
Like I said, about 1.5 hours of actual work and too dang easy. As far as the manufacturer and part #, I have absutively none idea. I imagine it was an HD part and it fit an HD bike. I bought it at a local "Motorcycle Swap Meet" (which in my neck of the woods means "sell the crap that fell of your Harley for way too much money") and I immediately popped off the HD logo and tossed it back to the wide-eyed greaseball that sold it.
NOW its a custom Triumph part on a Triumph bike. I will now put some "clarification" pics in my gallery. I hope this helps....... at least a little bit.