Servo5_function

HI All
I made mod kit for my PixHawk 2.1 to insulating the corner of the board.
In MP I have SERVO1_FUNCTION =33, SERVO2_FUNCTION =34, SERVO3_FUNCTION =35, SERVO4_FUNCTION =36 ,SERVO5_FUNCTION =37
But my ESC for motor 1 works only if connected to main out 5 .
What I have to change to be able to coonect to main out 1 ?
Regars