The rudder isn't actually "reversed" when you're flying inverted. It still makes the plane yaw in the same direction as it would if you were upright. Put yourself in the cockpit and think about it. Forget about the ground reference for a minute. That being said, for negative snaps (i.e. DOWN elevator) you use opposite rudder and aileron inputs whereas for positive snaps you use the same rudder and aileron inputs. Aileron input helps with a Pattern plane - it actually affects the way the wing stalls so be careful. The airplane does not roll with rudder or aileron in a REAL snap roll. It rolls because one of the wings is stalled. This happens because you applied enough elevator to reach the critical angle of attack AND applied some rudder to start the autorotation. To stop a fully developed snap roll you should use the same inputs that you would to stop a spin: opposite rudder and neutral or opposite elevator (opposite compared to what you used to enter the snap roll or spin).

John Pavlick
Team Black Magic