Mine was just for experimentation, but I removed the happ lense and mounted the aimtrak in the end of the barrell. I had to file some slots on each side of the hole in the end of the barrel. It's not pretty from the front, but it works.
I ditched the original cable and just have the usb cable coming out the bottom.
My place is in disarray at the moment, but I'll post a pic later if I can get to it.