Flex chart datatip position

I have created my own dataTipRenderer for a PlotChart and I am trying to change the position at which it is displayed. I have tried:

this.x -= (some 开发者_JS百科number);
this.y -= (some number);

Ive tried putting this code in the updateDisplayList function and when I set the data, but that didnt seem to move the datatip at all.

need to override the move(x, y) function since this is called externally to set the location after the object's data object is set.

override public function move(x:Number, y:Number):void
{
    super.move(x - 17, y - 40);
}