Taking LC's info one step further, to wire any microphone, if its a 4 wire mic, braid will be ground, one inside will be audio, set your DVM for continuity and attach one test lead to the braid,the other test lead to the other two wires, Rx wire willl show continuity without keying mic, tx will show it with the mic keyed.
You then match the wire after noting what's what and use LC's info to put same wire to same pin.
If its a 5 wire microphone chances are braid is ground,audio is inside itn leaving you 3 wires, two will show continuity with microphone unkeyed, one of those is switch common ground the other RX,
Try both wires to the last wire and the one that shows continuity with microphone keyed is TX
You then solder switch common to the same pin Braid/Ground on radio that Braid went to, good idea to twist it and braid and tin them together before hand, tin all wires and all microphone receptacles and you'll get a much neater job,
using a vice to hold plug is a very good idea as you will need one hand for iron, one to hold wires or if you haven't got asbestos fingers like me tweezers to hold wire in position as solder solidifies, nice shiney finished joint your looking for, preheat the receptacle before bringing tinned wire to it and it will be ready to go in seconds, extra solder comes to receptacle or iron, not iron to solder, a small tip size is advantageous in doing microphone plugs as its less likely to damage surrounding plastic insulator and wires a receptacles on plug thin and quick to heat.
good idea to use a 15-25w Iron and 60/40 solder, preferably Ersin Multicore or similar quality, preparation makes perfection.
One way to find the ground pin on radio without even opening it is to attach one test probe to negative lead of radio whilst unplugged from psu/battery and probe the 4 or 5 pins in the radio for continuity,the pin/s that show it are at board ground.
LC's just too keen to get inside there and work some magic, lol
If you want to do six/eight pin radios, the stage after finding the radio ground pin is to set your DVM To volts range of over 15v, 20 or 30 ranges is common, connect the black lead to ground (you can use psu black post or radio ground pin and probe pins with red lead looking for voltages around 5v to 13.2 or 13.8 range, pins with the 5v are almost always for up or down.
Pin with 13v range can be used to power speech processors, power mikes with dropper resistor and zener etc, but whatever you do do not probed it with a bare wire or even an insulated one as it will short circuit radio, and depending if you hit ground it can blow fuse, lift tracks if right fuse ain't fitted, shorting it too other pins can blow microprocesser, only a voltmeter set to volts can bridge this pin with ground.
If your not experienced I suggest you master takin on 4 pin mics before messing with 5,6 or 8 pin radios, its very easy to damage them.