Thanks Chris,
I have read the wiki it gives a good description of what to do, but im still at why and in what use case!
My quad receiver is wired up as PPM so i dont think i can separately wire a channel.
Is it essentially a choice between being able to control an axis on the gimbal with a transmitter vs have APM control the axes for stabilization?
thanks for answering my beginner questions. Ill hold off after this 
Alex