[BPWilliams]

I think the best way is to make a metal bracket that attaches to the frame through the trunk. Attach the belts to the metal bracket.
The way I did it, drill a hole through the glass and mount to a 6"X6" piece of plate steel. it works but not totaly secure! Also watch out for your seats hitting the back of the compartment. I cut mine near the top where the glass is sharp inside of the seat.
I am sure that lone star has a fix for this issue.

L8R,
Brian