Want to mod: PCEngine Mouse

[SuperDeadite]

Probably a long shot, but anyone ever tried to mod a PCE mouse?  I want to play through PCE Lemmings, but the buttons are swapped!
The right mouse button is "Button I".  Meaning the right mouse button controls everythng.  Using my middle finger all the time is a pain in the ass.  I can't even use the mouse left-handed because of where the Run and Select buttons are placed.