scroll horizontal

[paois1]

Hola amig@s
Tengo este codigo

Código:

function scroller():Void
{
	scroller_mc._y = scrollable_area_mc._y;
	tn_group._y = tn_area._y;
	sr = tn_area._height/tn_group._height;
	scroller_mc._height = scrollable_area_mc._height * sr;
	sd = scrollable_area_mc._height - scroller_mc._height;
	cd = tn_group._height - tn_area._height;
	cr = cd / sd;
	tn_group.setMask(tn_area);
	
	if( tn_group._height <= tn_area._height )
	{
		scroller_mc._visible = scrollable_area_mc._visible = false;
	}
	else
	{
		scroller_mc._visible = scrollable_area_mc._visible = true;
	}
	scroller_mc.onPress = function()
	{
		this.startDrag(false, this._x, scrollable_area_mc._y, this._x, 
					   scrollable_area_mc._y + scrollable_area_mc._height - this._height + 1);
		onDrag = true;
		this.onEnterFrame = function()
		{
			new_y = tn_area._y + scrollable_area_mc._y*cr - this._y*cr;
			cv = (new_y - tn_group._y) * scrolling_speed;
			tn_group._y += cv;
			if( onDrag == false && cv_old == cv )
				delete this.onEnterFrame;
			cv_old = cv;
		}
	}
	scroller_mc.onRelease = scroller_mc.onReleaseOutside = function()
	{
		this.stopDrag();
		onDrag = false;
	}
}

es de un scroll que va vertical... como puedo modificarlo de modo que el scroll quede horizontal??
Gracias de antemano