It's hard to see in this photo, but if the rack IS like the Coleman rack, it will come with brackets for wing style crossbars.
Basically, 4 pieces of plastic that snap into place on the bottom of the rack, then the rack is placed on top of the wing bars, and then 4 metal pieces are layed on top of the rack and tightened down with some bolts. I can take a close-up photo if you like.
Bart
EDIT: damn, beat me to it!