Lynn, I still have to put the set in my silver car so maybe I'll remember to actually take some pictures of the mounting plates I made. Otherwise, there really isn't much to engineer since GM offered this set up in the first gen cars and there are some nice details outlined in the Fisher body manual as well as Kurt's report on seat belts over at CRG.
http://www.camaros.org/seatbelt.shtml
I did have the belts made after I measured out what I wanted.