Rudder arming of a flying wing

I am flying a wing using an elevon output.
Since I have no rudder, I wonder how to arm it for the sticks
Thanks for the help

have rudder_arm set to 2 and make sure Arm_Required is set to 1 or 2. Arm by putting the throttle in the bottom left and disarm by putting it in the bottom right. You also have to disable and remove the safety switch.

Thanks. Done ! it is work.
Since I mapped CH4 on 5 and use it to control my camera it did not worked before.
Now I mapped it back to CH4 and use the rudder to manually rotate the camera. I will probably have to make a mix between CH4 and CH5 if I want mapping the camera with in the software.