If the brake light switch fits the mounting location and you cannot find an acceptable switch, you can still use it. You only need to add a relay with normally open and normally closed contacts. John Deere uses one in their MFWD circuit on 55 series tractors. I can get you a part number if you like--I don't have it in front of me at present. This relay is made by either Hella or Bosch.
Anyway, when the reverse lever actuates the plunger on the brake light switch, it opens the contacts. Hook up the relay so that the light power source wire goes to the #30 terminal and the wire going to the lights is attached to the #87a terminal(normally closed). Feed the brake switch from ignition switched 12 volts and have the switched wire feed the #85 terminal on the relay. Ground the #86 terminal and you are set.
A relay, especially one with normally open and normally closed contacts, is a very useful electrical component.
