I was going to make a follow-up post that I got it dissassembled, but then I forgot.
I got it apart, at the rear of the cylinder near the tailpiece, there is a spring clip thing that you described. You show an awl in the place where the locking bar falls into and pop the springy clip out.
As far as I'm aware, the Adams-Rite trip wires from Peterson don't work on locks with a closed tailpiece. I could be totally wrong, but you can't get into detail as this is the open section.
I was thinking about putting the Adams-Rite mortise setup on my front door.

Maybe I'll try to put it on a practice board instead. Does anyone know how to mount this thing on a door? I looked on the A-R site, but didn't get instructions that were very detailed.
"Lockpicking is what robbing is all about!" says Jim King.