ActionScript 3.0 :: Papervision Camera Orbit In Ellipse?

I'm in the final stages of my Papervision project and I need to have the camera orbit around its target in an ellipse rather than a circle on a mouse drag. The tricky part is I already am using some complicated logic to get it easing as well and I need them to work together.

ActionScript Code:
private function upHandler(event:Event):void {
isCameraRotating = false;
} private function downHandler(event:Event):void {
isCameraRotating = true;
previousMousePoint = new Point(mouseX, mouseY);
[Code] .....