Прокрутка колесом мыши

[adlopez]

Добрый день.
Ситуация в следующем. У меня есть прокрутка страницы с вот таким кодом:

scrolling = function () {
	var scrollHeight:Number = scrollTrack._height;
	var contentHeight:Number = contentMain._height;
	var scrollFaceHeight:Number = scrollFace._height;
	var maskHeight:Number = maskedView._height;
	var initPosition:Number = scrollFace._y=scrollTrack._y;
	var initContentPos:Number = contentMain._y;
	var finalContentPos:Number = maskHeight-contentHeight+initContentPos;
	var left:Number = scrollTrack._x;
	var top:Number = scrollTrack._y;
	var right:Number = scrollTrack._x;
	var bottom:Number = scrollTrack._height-scrollFaceHeight+scrollTrack._y;
	var dy:Number = 1;
	var speed:Number = 10;
	var moveVal:Number = (contentHeight-maskHeight)/(scrollHeight-scrollFaceHeight);
	
	scrollFace.onPress = function() {
		var currPos:Number = this._y;
		startDrag(this, false, left, top, right, bottom);
		this.onMouseMove = function() {
			dy = Math.abs(initPosition-this._y);
			contentMain._y = Math.round(dy*-1*moveVal+initContentPos);
		};
	};
	
	
	scrollFace.onMouseUp = function() {
		stopDrag();
		delete this.onMouseMove;
	};
	btnUp.onPress = function() {
		this.onEnterFrame = function() {
			if (contentMain._y+speed<maskedView._y) {
				if (scrollFace._y<=top) {
					scrollFace._y = top;
				} else {
					scrollFace._y -= speed/moveVal;
				}
				contentMain._y += speed;
			} else {
				scrollFace._y = top;
				contentMain._y = maskedView._y;
				delete this.onEnterFrame;
			}
		};
		
	};
	btnUp.onDragOut = function() {
		delete this.onEnterFrame;
	};
	btnUp.onRelease = function() {
		delete this.onEnterFrame;
	};
	btnDown.onPress = function() {
		this.onEnterFrame = function() {
			if (contentMain._y-speed>finalContentPos) {
				if (scrollFace._y>=bottom) {
					scrollFace._y = bottom;
				} else {
					scrollFace._y += speed/moveVal;
				}
				contentMain._y -= speed;
			} else {
				scrollFace._y = bottom;
				contentMain._y = finalContentPos;
				delete this.onEnterFrame;
			}
		};
	};
	btnDown.onRelease = function() {
		delete this.onEnterFrame;
	};
	btnDown.onDragOut = function() {
		delete this.onEnterFrame;
	};
	
	if (contentHeight<maskHeight) {
		scrollFace._visible = false;
		btnUp.enabled = false;
		btnDown.enabled = false;
	} else {
		scrollFace._visible = true;
		btnUp.enabled = true;
		btnDown.enabled = true;
	}
};

scrolling();

Мне нужно вставить еще возможность прокрутки колесом мышки, а я никак не могу разобраться. Помогите пожалуйста.