RC Passthrough only when Armed?

I am using the RC passthrough function to control a payload using a switch on the transmitter. However, is it possible for the RC pass through to only function after the system is armed? This would prevent the operator from controlling the payload until the system is armed.

And similarly, it would be nice for the landing gear to only function after the system is armed to prevent inadvertent retraction of the gear when on the ground.

Will this be helpful ??

http://ardupilot.org/copter/docs/parameters.html#brd-safety-mask-channels-to-which-ignore-the-safety-switch-state

That’s close, but that’s a safety switch, which is different than arming.

I would like to passthrough rc11 and rc12 (from radio) to aux3 and aux4.

I only need to enable passthrough on servo11 and servo12 (servo_function 1) ?

I have tried but doesn’t work

Could you help me please ?

These parameters:
SERVO11_FUNCTION 61
SERVO12_FUNCTION 62