Gimbal yaw angle from relative_to_frame to relative_to_earth

Hi. I have the fixed wing(fw v4.1.0) and mounted 2 axis gimbal (aw pitch) (simple bgc32 alexmos fw 2.70b4 with encoders).
When I do in mission planner “Point camera here” gimbal keeps that point tracking but when I switch it to rc targeting or mavlink targeting it moves correctly but the when plane changes its yaw gimbal also changes its yaw. But I need to keep the last yaw target angle.
How to do it?