Animation looks fine in gmax but doesn't work in FSX.

I've created an aircraft model in gmax which uses flaperons - i.e. combined flaps and ailerons. I need to define animations for these two functions but gmax can only define one animation. The animation manager allows me to define time limits for an animation though, so I've tried defining the aileron movement from time 0-100 and the flap movement from 101-201.The gmax animation does exactly what I want but when I export it to FSX it doesn't quite behave as expected. I can apply flaps as expected, but the ailerons will only move in one direction! The ailerons start off flush with the wing but for the left aileron this is the lower limit of movement and for the right aileron it is the upper limit.To be precise, my animations are l_aileron_percent_key Time 0: left aileron down 20deg. Time 100: left aileron up 20deg. r_aileron_percent_key Time 0: right aileron up 20deg. Time 100: right aileron down 20deg. l_flap_percent_key Time 101: left flap up. Time 201: left flap down. r_flap_percent_key Time 101: right flap up. Time 201: right flap down.The animation manager dialog mentions "markers" and "events", but I've no idea what these are about or whether I need to define any.Just to complicate the situation, I'm actually driving the surfaces through the SDK using the simulation variable AILERON POSITION. This is defined in the documentation as having units Position (-16K to 0) but I haven't had much luck taking this literally. I'm now specifying the units as "degrees" and this at least produces a response, even if it isn't quite the right one.