Gary, I had the exact same situation, need to have those bags!!! Liek Rodburner said, I mounted them directly to the rear fender. I drilled a hole in the fender, just bolted them on. The omly tricky bit is making sure you secure the wiring to the underside of teh fender, I am using wire clamps bolted through the old tailight mounting holes...
I have a 150 series rear tire, it does not interfere at all with the lights, they clear even when completely bottomed out on the rear shock.
Anyway, heres a picture.
