Changing outputs for ailerons and tails on a v-tail

Im using an airbot mini it only has bec power the the aux rail no the main rail how do i swap the outputs for the ailerons and tail so i can use aux. all i can find is saying i need to write firmware to change this is this true?

It might be easier to use a short servo cable to jump the power from the aux to the main.

the airbot mini board we are using the main outs are not connected so i would need to make a wiring harness running to each servo and on the number of machines im making that would be frustrating at best.