I replaced the Hitec 75BB retract servos for A7000 spectrum retract servos also I had to change the servo plug as it was very loose in the extension socket, I think it would require spectrum extension leads, But as the sockets were built in to wiring loom for the retracts it was easier to change the servo plugs, Now I can control the speed of the servos.
http://www.youtube.com/watch?v=B0IlS...ature=youtu.be
http://www.youtube.com/watch?v=sVqT2...ature=youtu.be