[Azy]

Написал по мануалу:

class B1 extends mx.controls.CheckBox
{
	static var symbolName:String	= "B1";
	static var symbolOwner:String	= "B1";
	var className:String			= "B1";
	
	function B1() {
		init();
	}
	
	function init():Void
	{
        createChildren();
		super.init();
	}
	
	function draw(){
		super.draw();
	}
	
	function createChildren():Void
	{
		size();
		invalidate();
	}
	function size():Void
	{
		super.size();
	}
}

Опять непонятно... =(