Relay pin identification on CUAV V5 Nano

Hardware Multirotors
1

Im running arducopter 4.2.0 on Cuav V5 Nano and trying to configure camera relay shutter pin on AUX 1 pin.

I have set RELAY _PIN = 50 ( which mentioned there is AUX 1 on mission planner)

But pre arm message gives warning that set SERVO 1_ FUNCTION= -1( GPIO).

I want to configure it on AUX 1 instead of MAIN port 1.

2

Then set pin 58. From the Hwdef file:
PA5 TIM2_CH1 TIM2 PWM(9) GPIO(58)