Not sure how common of an issue this is, but... when I got my car, the seat back for the drivers side was broken. Luckily, the broken back was in the trunk, and I found the metal tab under the seat!
The one tab was torn right off, and there was a huge crack in the bottom opposite corner (was like a hinge!).
I've run into almost the same problem with Fiero headliners, and fixed them all - so figured I'd do the same to this. And it works fine.
Fibreglass resin right after it's mixed is very watery and will soak right into the board. I lined up the broken off part with where it should go (you could see an outline of the holes still). Put a square of tape around the bracket for alignment. Poured resin on the board and let it soak in for a minute, then placed the bracket in place. Poured more resin over top of the tabs.
The cracked part was even easier. Just wiggle the broken parts back together as best you can. Put a weight on it (in the middle for this case) to hold it flat to the table. Then just start pouring resin carefully along the crack, letting it soak in. Keep adding until you're happy. Don't let it run off the edge!
Added a bit more across the other tabs just for good measure.