I would start by finding or creating wiring diagrams of each microphone. There are web sites out there with lots of microphone pin-outs. If that doesn't work, open them up and create your own wiring diagram. Once you do that, I'll bet the reason will be staring you right in the face. Those same diagrams may help in future trouble shooting also. http://www.mods.dk/
would be a good place to start. you could download your radio service manuals here and they will show the microphone connections.
Be carefull plugging microphones in radios that weren't made for them as you can do serious damage to both radio and microphone (e.g. shorting the 8 volt bias to ground and burning out the 8 volt regulator).