can't make spark VideoDisplay work in as3 project

Question

package
{
    import flash.display.Sprite;

    import spark.components.VideoDisplay;
    import spark.components.VideoPlayer;

    [SWF(width="850", height="630")]
    public class mainApp extends Sprite
    {
        public var com:VideoPlayer;

        public function mainApp()
        {
            var d:VideoDisplay = new VideoDisplay();
            addChild(d);

            d.addEventListener("creationComplete", function(event:*):void {
                d.videoObject.attachCamera(null);
            }
        }

    }
}

videoObject is always null. If it's flex project it works perfectly. In pure as3 it's not. Anyone know, what i'm doing wrong???