Orbiting in Surround - horribly difficult?

Pg 225 of the manual.
Working in surround the x and y axis of the surround field between the four speakers are saved on seperate automation lanes. Apparntly, this is the reason why steinberg, have not automated the ‘Orbit centre’ knob. It needs two paramenter lanes.
I hope steinberg wil get around to providing an algorithm to do this, or some kind of surround autopanner, but in the mean time does anyone know a way of doing this without resorting to manual mouse movement recording (which is very off target).

Its something I should like to do quite a lot for a piece I am working on. All I can come up with is using two sine waves in the automation lane - but this is tricky especially when you take in radius.

Seems horribly difficult for such a simple thing