You can use small nail as a punch and hammer the thing out. It'll come out a little bit, then press the lanyard loop against a table or floor and pull the rest of the pin out by hand.
Push it back in the way it came out. By hand. Just neutralize the opening by pressing the lanyard loop against a table or floor.
I haven't found an alternative backstrap for the Phantom yet. Don't really need one I don't think. I would recommend going through the trouble for a 15 lb hammer spring.