I am putting together my first airplane. The plane is an electric easystar with a futaba 6XA radio. Channel three is for the throttle, channel two is for the elevator. I am able to plug these in without a problem. Channel four is used for the rudder. No go. It will work if I plug it into channel one which is for the aileron servo. Nothing happens when plugged into the correct channel. There are a bunch of functions on the radio. I pushed reset and still cannot use the rudder. Any suggestions?