Jan,
Ok, thanks for that information. If you add support for mouse control, cockpit switches can still be employed by putting the aircraft on autopilot, setting the switches/controls as desired, and then disengaging the autopilot. Even better, have a keyboard shortcut for entering mouse cockpit control mode where FS 2 automatically maintains current heading and climb, descend, or level flight. Then let the user press a shortcut to return to flight control using the mouse.