I've done it to an Ultimate Big Boy (purchased used), the back rest, and to an Interstate trunk back rest. I used white grease pencil to mark the locations of the studs (while the cover was still intact), and then pulled away just enough of the glued on portion of the seat to stick the studs through.
I purchased my studs directly from Mustang Seats. They are Nickel, and probably the best available. Installing them was pretty easy... I just made sure that they were aligned correctly, pushed the two 'spikes' through the material, and bent the spikes over with a flat headed screwdriver.
This was quite a few years ago, but here is a picture showing how things looked when done -

Black Dog