I've done a bit of composite molding, and as far as I know it is just glass. Rough it up a bit (100-200) and use some slow epoxy. Test a couple of small bits and see how it works (a.k.a. - beat the living crap out of it with a hammer) before using it on your intended "finish" material.
Keep in mind that a lot of higher end "G" (fiberglass) products, as well as carbon/kevlar products are produced in a vacuum (atmospheric clamping) for maximum adhesion. If you can rough up, epoxy, and place in a vacuum for curing you will get closest to the original specs.
That can be accomplished a variety of ways but the simplest method is to rough it, epoxy it, wrap it in a bit of high-mil plastic, and pull a bit of vacuum (a brake bleeder will work nicely - or even a vacuum cleaner).
After that just use it as you always would.