I believe the optic board for the Tron is proprietary so it is not plug and play compliant for an Optipac. I have seen one hack where you hack the traces on the Tron optic board and hook them up directly to an encoder, but this may be somewhat tricky.
I removed the Tron optic board and ended up using a mouse PCB mounted on a piece of wood that just happened to be the perfect dimensions to screw on to the bracket where the original Tron optic board was.
I can't remember what mouse it was, but it was perfect, and it works great. I will take a picture of it when I get home, which won't be till Thursday or Friday... I am on the road right now working... in scenic Newberry, SC... testing Komatsu bulldozers for regulatory compliance...