FW position controller offboard control with PX4-messages and ROS2

Hello, I am running a simulation with PX4-1.14 SIL. My aircraft is a VTOL.
I switch to offboard mode and take off as MC. At a certain altitude the aircraft transitions to FW and a ‘‘trajectory_setpoint’’ message is sent to the PX4 with a 3D target point to go to. I use ROS2 and DDS to communicate with PX4.

From data logs analysis i observed that when the transition to FW is finished, the throttle goes to zero and the aircraft looses altitude and crashes to the ground. It seems like the '‘trajectory_setpoint’ message doesn’t have any effect - it never reaches the FW position controller.

My question is how is it possible to command a FW aircraft to move towards (or to) a 3D point in space using ROS2 and PX4-messages, and the PX4 position controller?

In the PX4 user guide I found that only with a MAVLink command can do this: SET_POSITION_TARGET_LOCAL_NED (Offboard Mode | PX4 User Guide (main))
Is there any way to avoid using MAVLink and stick with ROS2 and PX4-messages?