Genesis,
You should be able to get brass hardware at most hardware stores. Home Depot and Sears P&H in my area have them. The crossover panel has a thin foam seal around the perimeter. You may need to pry a little bit to get it started. The botttom crossover board is in wood alignment slots, so it will need to be slid out straight (not angular). The crossovers in the SC-Vs are surprisingly heavy, this may also contribute to your seemingly "stuck firmly" crossover.
Once you have the crossover out of the enclosure, I would also suggest changing the way the the lug panel is mounted. It will allow you to use any lugs on the back of the Dunlavys. This may be difficult to describe, I'll do my best.-- When SC-Xs are delivered from factory, it is nearly impossible to put large, inflexible cables (ex.Syn Res Des Refs) on them. If the ring (spacer) that is sandwiched between the lug panel and the exterior crossover panel is moved to behind the lug panel, there is then no well that is caused by that ring (spacer). If the above description is insufficient, I believe I have some digital photos around here if anyone would like them emailed to them.
Lastly, I would also enjoy a description of how non-ferrous fastening materials effected the original sound.
Thank you, Aaron