Actuator Commands

I am trying to control servos on a fixed wing plane directly from a companion computer using MAVROS. I have successfully armed the flight controller and changed it to “OFFBOARD” mode before publishing to the actuator_control MAVROS topic. Unfortunately I do not see any movement in the servos that I am sending commands to. Is this the correct method to send off board actuator commands? If so, what am I missing here?

Thanks!