easy fix, just can't remember exactly how!!! lol I have a 100esl72r, same as yours? That switch in the remote is perhaps the biggest problem with the hydro- electric shift; at least, I think so - luv mine! I ran wires to two toggle switches. One switch stays on for forward, flip the other on and you have reverse. Just can't remember which color wires go where?
Wish I could tell outright, but I'd have to tear mine apart to see. Google it, I think it's somewhere here on Iboats? and it would be better explained than what I could tell ya....