I broke two of the mounting tabs on the rear fender cladding while installing a trailer hitch. I used a 2 part epoxy called PC-7 to repair the tabs and it worked like a charm. The mix is thick so you just press it into place with a disposable putty knife but it does 'flow'. It takes 24 hours to fully cure but gets tacky-firm within an hour. If you use it, remove the cladding from the vehicle so that you can orient the repair site so that gravity works for you rather than against you.

PC-7 is available at True Value hardware stores but I even saw it at Lowes once. The best part is that it is almost the same color as the cladding so if you get messy, it won't show. It seems to have a very similar coefficient of expansion as the plastic cladding so temp changes shouldn't cause it to pull loose.

They make PC-11 as well but it's white and is for marine use. I think the finished product with PC-11 is more brittle so I wouldn't recommend it for your application.

BOL