Using a BitmapImage in a mobile skin

Question

Hello,
Is there a way to use a BitmapImage as a skin part in a mobile skin? Since it does not inherit from DisplayObject, I cannot add it using the addChild method in the skin.
I tried the following:
override protected function createChildren():void
     this.imageDisplay = new BitmapImage();
     this.addChild(this.imageDisplay.displayObject);
But I get:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
     at mx.core::UIComponent/addChild()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UI Component.as:7137]
...as it appeards displayObject is null at this point.
Any ideas?
Thanks!

Answer 1

Stupid me! I didn't think to just look at the ImageSkin source in the mobiletheme. 
override protected function createChildren():void
    // create container for holding the currently displayed image
    imageHolder = new Group();
    addChild(imageHolder);
    // required skin part; the Image component will set this directly
    imageDisplay = new BitmapImage();
    imageDisplay.left = 0;
    imageDisplay.right = 0;
    imageDisplay.top = 0;
    imageDisplay.bottom = 0;
    imageHolder.addElement(imageDisplay);
Looks like they just wrap it in a Group first.