Attaching handles to rear body...HELP

[biounlimited]

Hey everyone, I am trying to attach some handles to the rear of my 8X8 Avenger. Tried some "rivnuts" basically a rivet with a 1/4" nut in the middle, but they pull out of the body when crimped ( plastic is too soft)! How do people here attach handles etc. to the rear tub? Would 1/4" screws hold? Body looks to be approx. 1/4" thick where I want to mount them, but they have to be able to hold up to abuse as grab handles. Thought about bolts but I can't access the under side to put nuts on , without removing upper body ( not an option). Any help would be appreciated.

[trebmaster]

you can use drywall butterflys that you can get at any hardware store

[mark m.]

Can you fabricate a backup plate to rivet through to?

[jerseybigfoot]

They make backup washers for the rivitnuts

[biounlimited]

for the back up plate, or washer I can't access the back (it is under the seats, see pic where I mounted). Used "Jack Nuts" and they seem to be strong enough.......time will tell. The Jack nuts expand when tightened up, and have a 1/4" nut in the middle. Handles are stainless core with soft rubber outer.