Gimbal control in Harmonic

In Gazebo Classic, I used a plugin to control a gimbal via Mavlink messages:

<plugin name='gimbal_controller' filename='libgazebo_gimbal_controller_plugin.so'>

What is the best way of controlling a gimbal by means of Mavlink messages (using QGroundControl for example) in Gazebo Harmonic?
I am using PX4 model controller.
Cheers