Recommended ways to set rivets on trigger gaurd

Well, I tried to smash one of the rivets in the trigger gaurd area. For the most part it worked ok, but it is a very difficult place to get to. I used a piece of 7/8'' round steel and a plate on the other side. However, the round steel wanted to bend over a bit and bend the bottom of the reciever. I'm trying to figure out a cheap way to do this without damaging my receiver. I'm on the waiting list for 762's jig, but would like to go ahead and finish mine. Any suggestions. I can't remember if HCpookie ever perfected this section with the bolt cutters or not. Anyone remember? I sat down for a while with a set to see if I could figure a way out to make them fit and got stumped. I open for ideas...I know Hotbarrel has been sucessful with something similar to what I'm trying.