Here's a Momentary Contact Carling Rocker
Switch. Looks like this

It's like the Horn Switch in our boat. A boat supply place might have something. If dimensions don't match, you could buy a cheap dollar store white cutting board, and use it as material to make an A-Dapter Kit.
But first: your Battery Disconnect should cycle if you simply touch those two switch wires together. If it's OFF, one touch should turn it ON. If ON, one touch should take it to OFF. If that doesn't happen, something else is wrong.