Ya, you just want to break the surface shine, and make it dull in easy to understand terms. As long as you clean it well before you goop on the filler, it will bond more than a-ok.
You can use a few different name brands, these will be available from any local auto paint supply store. SEM - Flexible Bumper Repair and Dura Mix (3M bought them so not sure what the current name is.
In General...get you some FLEXIBLE plastic bumper repair stuff...sand your bumper in the area of the ribs, goop it on, and sand it smooth. It might take about 3 coats to get it perfect. Then prep, primer, paint, clear coat, done.
~F~
