Adding camera gimbal to Gazebo Garden simulation

PX4 Autopilot
1

I’m trying to add camera gimbal to the x500_mono_cam example model.
Running Gazebo Garden and ROS2 humble.

I modified the model to add a joint and a controller. In PX4-Autopilot/Tools/simulation/gz/models/x500_mono_cam/model.sdf,
from the fixed joint,

    <joint name="CameraJoint" type="fixed">
      <parent>base_link</parent>
      <child>mono_cam/base_link</child>
      <pose relative_to="base_link">.12 .03 .242 0 0 0</pose>
    </joint>

I changed it to revolute, controlled by a servo:

   <joint name="CameraJoint" type="revolute">
      <parent>base_link</parent>
      <child>mono_cam/base_link</child>
      <pose relative_to="base_link">.12 .03 .242 0 0 0</pose>
      <axis>
        <xyz>0 1 0</xyz>
        <limit>
          <lower>-1.57</lower>
          <upper>1.57</upper>
        </limit>
        <dynamics>
          <damping>1.000</damping>
        </dynamics>
      </axis>
    </joint>

    <plugin
      filename="gz-sim-joint-position-controller-system" name="gz::sim::systems::JointPositionController">
      <joint_name>servo_0</joint_name>
      <sub_topic>servo_0</sub_topic>
      <p_gain>10.0</p_gain>
    </plugin>

I have also set Servo function to gimbal pitch in the frame config, in:

PX4-Autopilot/ROMFS/px4fmu_common/init.d-posix/airframes/4001_gz_x500

param set-default SIM_GZ_SV_FUNC1 421

When I run simulation, In “Actuators” tab in QGC I can see the gimbal pitch control slider, but when I move the slider camera does not move.

Am I missing something, or doing something wrong?