Change yaw in Guided mode

I want to make the copter point at an object in guided mode.

I now have control of the copter via UDP and can make it move in X,Y and Z using the SET_POSITION_TARGET_LOCAL_NED.

However, I can not make it rotate i.e. change yaw.

There is a part of the SET_POSITION_TARGET_LOCAL_NED command reserved for yaw but apparently it’s not implemented in Copter.

Do you have an idea on how to change yaw on guided mode?

I have now tried using MAV_CMD_CONDITION_YAW, which works, but doesn’t allow me to specify a rotation speed. Is there a better command for smooth movement?