ArduPlane Arming

In setting up arduplane on an APM 2.5 board that will go in a skywalker 1900, I notice that I do not have the ARM Disarm function that I am used to with the arducopters.

I start off in Manual mode on the controller and immediately the prop will spin with input from the throttle stick. Traditional disarm commands through the controller have no results. Also when clicking the Arm/Disarm button on mission planner I get an error message “unable to arm/disarm MAV”.

I am going through the wiki again trying to find documentation about this issue but any help would be greatly appreciated.

In recent releases there is the ability to arm:
plane.ardupilot.com/wiki/arming-throttle/
currently to disarm you need to use the GCS, not the rudder, as zero throttle and left rudder is a common stick movement for planes.
Cheers, Tridge