I've repaired a MyLaps transponder, and it's just like Flame said, trace around the seam of the plastic case with a sharp hobby knife till the case separates, then it's just like a previous generation AMB transponder.

I like use a soldering iron to soften the epoxy, both the black exterior and the clear filler AMB likes to use on the inside. Just a touch the iron to the epoxy for a few seconds and carefully pick away at it with a tool of your choice, just don't try to remove too much at once or else you force your own hand to buy a new one.

Desolder your broken leads, and either trim and reinstall, or replace with the wire type of your choice. Make sure you keep good notes about the polarity of the wires.

I like to fill in the epoxy gaps with hot glue. When you're all finished, cleaned and sealed up, put the outer case back on with some thin CA.

I hope I've been somewhat clear with my experience...sorry I don't have any pictures to share.