Controlling a DC motor via R/C

Hello. I posted this question elsewhere then realized it probably belongs here. I'm building a combat robot and was wondering if there is a way to control a DC Motor Controller (12v) that has a potentiometer or pot on it with a receiver from an RC unit instead.

I know there are some that are made to this such as the IFI Victor 884 and the Vantecs but I already have some DC controllers that have potentiometers that I really want to use/ convert.
I do not want to simply connect a servo to the potentiometer to control it. I want it to be solid state. Is there a way to wire it up or does somebody make an adapter for doing this? Thanks!

You could replace the POT with a digital potentiometer, but I see no simple way of interfacing one with a RC receiver since they all take serial interfaces or digital interfaces with a bunch of control lines.