Loss of clock and display when replacing radio
 

I have a 2007 Mazda3.

The clock and set buttons for the trip computer are part of the stock radio. So when that's removed you can't set the clock or access the trip computer.

I think it might be possible to wire a couple of buttons to the wiring harness to set the clock and access the trip computer.

Has anyone tried this?
Does anyone know anything about how the radio communicates with the display?

I'm planning to get an aftermarket radio soon. If no one else has tried this I might give it a shot.

Thanks!