Mavros plugin callback isn't called when message is received

ROS / MAVROS / MicroDDS
1

Hi

We have are receiving a mavlink message SCALED_PRESSURE3 in our autopilot and we want to have a call back for it every time we receive it.

We created this plugin to publish a topic everytime we receive that message:

#include <mavros/mavros_plugin.h>
#include <bev_uav_msgs/Ambient.h>

namespace mavros {
namespace extra_plugins {

class ScaledPressure3Plugin : public plugin::PluginBase {
public:
  ScaledPressure3Plugin() : PluginBase(),
    cc_nh("~ScaledPressure3")
    { }

    void initialize(UAS &uas_) {
        PluginBase::initialize(uas_);
        pubScaledPressure3 = cc_nh.advertise<bev_uav_msgs::Ambient>("sensing", 32, true);
    }

    Subscriptions get_subscriptions() {
        return {    
            make_handler(&ScaledPressure3Plugin::handle_command),
        };
    }

private:
    ros::NodeHandle cc_nh;
    ros::Publisher pubScaledPressure3;

    void handle_command(const mavlink::mavlink_message_t *, mavlink::common::msg::SCALED_PRESSURE3& msg)
    {
        ROS_INFO_STREAM("External sensor published");
        auto ambient_msg = boost::make_shared<bev_uav_msgs::Ambient>();
        
        ambient_msg->header.stamp           = ros::Time::now();
        ambient_msg->header.frame_id        = "External Barometer";
        ambient_msg->temperature            = msg.temperature;
        ambient_msg->pressure_type          = 0; // Absolute
        ambient_msg->pressure               = msg.press_abs;
        
        pubScaledPressure3.publish(ambient_msg);
    }
};
}    // namespace std_plugins
}    // namespace mavros

#include <pluginlib/class_list_macros.h>
PLUGINLIB_EXPORT_CLASS(mavros::extra_plugins::ScaledPressure3Plugin, mavros::plugin::PluginBase)

We have addded this to our CMakelists and .xml file.
When we launch ros we see the plugin being loaded and initialized. In QGC we have the SCALED_PRESSURE3 at 2hz but the callback is never called.

Any ideas that might help why we can’t callback this message?

Thanks.