@gtranquilla, I owe you a beer! I can arm now!
For Spektrum users, AUX 1 natively connects to the 3-way switch labelled "Flap/Gyro" with positions 0,1,2. First connect the AUX 1 on your receiver to the "U" port on the MC. Then set the 3-way switch to middle setting "1" and on the Spektrum's...