This should help you on how to mount it. Looks like it attaches right to the rails on the sides of the frame.
http://img525.imageshack.us/img525/5550/78462919yn5.png
Best of luck!
LSC Darkside 451
EDIT: My mistake. I got my inside and outside messed up in that pic. Check out IFI, they have the PDF for it there now.