Second Kicktower/pedal Issues

So I have the Alesis Nitro Max kit right, and I bought a second kick tower instead of double bass (figured it would trigger more accurately than double kick on one pad), and I also bought the expansion kit with the extra tom and cymbal. My problem is that even when I split one of the toms to make 2 toms, (so that I can plug the kicktower into the tom input), it half works, whichever pad it decides is the “rimshot” trigger, has an insane threshold so I have to hit it hard for it to even register, rolling and even just hitting it twice fast just doesnt work. Am I doing something wrong? Should I split it a different way or something? Also Im trying to just use the module on its own so is it just a straight up limitation of the module?