i believe he looked at pics of my setup a little too much.
the rubber insert can be pulled straight out, and you can take a drill bit to it (by hand) just to tear a small hole in it. Then wire up the led, push the wires through the hole and pull then until the led fits snug in the hole. I'd suggest sanding it down until its level w/ the inner recessed part.
but thats how i did it... maybe he did something different.