[flexcoders] How to draw background in IconItemRenderer

[j2me_soul]

this is my code:
 
override protected function updateDisplayList(unscaledWidth:Number, 
unscaledHeight:Number):void{
    super.updateDisplayList(unscaledWidth, unscaledHeight);
    this.graphics.beginGradientFill(GradientType.LINEAR, [0x2e3e4e, 0], [1, 
.7], [0, 255]);
    this.graphics.endFill();
   }
 
the background is always the default gray ~