OK, nobody has replied but there are lots of views, having looked into this problem I think I see why and the solution is NOT easy.
1) Get yourself an XLR socket that fits your microphone plug and some audio coax. Wire the shield of the coax to pins 1 and 3 and the center core to pin 2. Close up the XLR socket as this bit is now done.
2) The order of the eight microphone connector pins from left to right is as follows:
Down button, Up button, +5V, Microphone ground, Microphone, PTT, Ground, Fast button. To check that you are looking at things the right way around check for continuity between pin 7 and the chassis of the rig.
3) Wire your foot switch between the ground wire (7) and the PTT wire (6), check your work carefully then apply power and test.
4) Connect the shield of your microphone cable to the 4th from the left (Mic ground) and the center wire to the 5th from the left (Microphone). Check your work carefully then apply power and test.
However...............................
No consideration has been given here to output levels. If your microphone has a low level output then you're good to go, if it has a preamp and a line level output then this won't work and you will need to go via a mixer, especially if the microphone uses phantom power.
Also, those eight pin connectors are a pain in the ass and not meant for audio work. The easiest way to get one for this task is a scrap network cable , cut one end off about 3cm from the plug then CAREFULLY check the connections.
Finally, an essential disclaimer. All of this information has been provided in good faith but if you get it wrong it could kill your rig. No liability is assumed by the author of this post and it should be noted that the FT-897D is not intended to be connected to an XLR microphone.
Peter DL8OV.