Nice plane and radio. A while ago we converted a PCS, and a Kraft Gold Medal to 2.4GHz using Orange RX DSM2 modules and the original encoders. All you need to do is to add a pulse inverter to the encoder output (2N3904) and run the encoder on 6 volts using an LM317. Of course, if you use a modern encoder, you get reversing and rates and extras. I'm currently using Phil-G's arduino encoder, it's super simple to wire up as it uses 3 pin Futaba J plugs.