Figured I'd provide a few pics of my old Rally Packs installed on my Roughhouse in case anyone was interested in seeing how it can be done. These were originally installed on my sport touring bike but I find I get more use out of them around town. Because of the file sizes I have to send three pics on three separate postings.
Here is a view of the attachment that would usually go around the foot peg of a motorcycle. . .but in this case I found a vent hole for the side cover worked fine.
And here is the final pic showing the "over the top" straps. The seat opens and closes without any problems but you do have to put a slight bit of pressure on it while closing. The straps will conform. I put some heavy duty electrical tape over the paint where the buckles are so as to avoid any cosmetic damage. Also, the strap that would usually go around the license plate bracket of a motorcycle fits nicely on the luggage rack. I did one extra loop on each side to take up slack and keep it secure.