The micro switch in my key fob has broken off.

In all the radios I've worked on the switches also have four terminals but they are always in pairs. That allows the designers flexibility in running the wires on the circuit board. They can connect to either pin, whichever one works out better. There are never two independent switches built into one so you are not going to disable one function by not soldering some of the pins. The unit only puts out one signal per button. If different functions are initiated by pressing the switch in a certain sequence, that is figured out by the receiver, not the key fob.