Yes, that's possible.... Connect the Pitch and Roll servos via F1 and F2 to the WKM...these two will be stabilized. The third servo - Pan/Yaw - can be connected to any free channel of your receiver and assign it a knob or slider on your transmitter to that channel, as long as it's not used by WKM. Pan/Yaw will not be stabilized that way, but nobody needs that anyway.
Chris