I need to install a one piece fiberglass shower stall into a 3' x 3' wall pocket built of all steel studs. Will screwing through the fiberglass shower into the studs be enough to support the shower as it would with wood studs? Or should I replace the steel with wood studs? Or should I put some sort of backing in? If backing is the answer, what is the best way to do this with steel stud for the shower install?