Gripper not working in auto mode

ArduCopter Copter 4.3
1

Cannot get gripper to work on auto missions.
Using copter4.37.
works from transmitter.
The gripper is EMP3

2

SOLVED! set servo (9,10,11,12) which ever servo you chose for passthru.
on the Plan page when setting a mission insert do_set servo at the gripper drop wp.Then set servo number in first field and 1100 pwm in the second field to disengage the gripper.YEAH!