I had a customer that wanted a Razer stick modded for PS4, so he shipped it to me directly from Amazon. He wanted a visual documentation of the process, so I took extra care and took a LOT of photos. I just realized I forgot to show where the other side of the wires went, but basically since there is an extra set of pins that connect to the buttons, I used wires similar to these to solder one side to the FC4, and the other end gets placed onto the pin headers. Minimal soldering needed, very stable, and easy to undo!
Anyway, onto the photos! Hover over the photos to see my caption and click to enlarge.