I assume you want to disable nose leg steering when the wheel is retracted. The easiest way is to create a new mixer with two input lines, rudder and fixed value, then assign the retract switch to switch between the two inputs, Mx1,2,3 and Mx1,2,3,N on the Royal, on the Profi just assign the retract switch as the mixer switch, Assign the mixer to the steering servo.
This way when the wheel is retracted the input to the servo is changed from rudder control to the fixed value. Set the fixed value in the menu to the stored position of the servo.
