Yes you can do that. You need to get the mic, ptt ground, etc to the right pins on the DB-25.
Here's the problems;
Are you going to use a X90 mic? How are you going to connect to the weird round connectors. Mates to that are just not out there. You could use a mic with an RJ-45 connector, but they are not as nice as the 90 mics.
You will need to pick an I/O pin as PTT and then program the radio to use that pin as PTT.
90 series radios are not set default for mic audio at the acc connector. A couple of jumpers will have to be moved inside the radio.
Barring that, no problemo.