I think any of the cycle super-stores, like J&P, JC Whitney, etc. would have brackets. The link I posted for Accessories International should also have brackets. Just get a set for the Honda 750 Magna. The hole lined up perfectly with the fender strut mounts. They are now about $75, think I gave Phil sold me his set for $30. There was a set in the classifieds a few weeks back.
There are four grommet holes on the back of Saddleman bags so you can use their quick-disconnect yoke (not needed when bolting them to a bracket). I lined up the top of my bag with the top of the fender support piece, two of the holes lined up next to a grommet. Saddleman sends you two extra rubber plugs for the extra hole on each side. I called Saddlemen and asked for two more rubber plugs, which they overnighted at no cost to me. (the yoke uses three grommet holes, so the two plugs supplied fill those holes)
They supply an elastic strap on the bottom, which I initially used to secure to the bottom of the bracket. Last year, I added another bracket in the center of the bottom of the bracket and removed the strap (quick disconnect).
So far the bag have held up beautifully, and despite being in quite a few soaking rains, my stuff has always stayed dry, didn't quite expect that but a nice bonus. The Large size just hold my jacket with liner crammed in one side. If you carry a lot, the Jumbo may be the size you need, I thought they were a little over-sized. I do think the Jumbo's look great with a solo saddle setup.
