Error Subclassing System.Control

I am trying to write my own component (!) based on the core 'classes' of of ActiveWidgets.

To start I've prepared a Control Object :

if (!AW.ControlPane) {AW.ControlPane = {}}

AW.UI.ControlPane = AW.System.Control.subclass();

AW.UI.ControlPane.create = function(){

var obj = this.prototype;
var box = new AW.HTML.SPAN;

obj.setClass("ui", "controlpane");
obj.setClass("controlpane", "control");

box.setClass("list", "box");
box.setContent("html", function(){return this.getLayoutTemplate()});
obj.setContent("box", box);

};

but ..

two error are displayed : both related to the object not having a method available. obj.setContent("box","box") ; is not valid . Why not ?

I have subclassed the System.control which subclasses System.Control.HTML which has the setContent method.

So why is not visible to me ? I have pulled my code for the AW.UI.List code - which does seem to have the method available ??

All help would be great

OK - small update the line giving the problem is :

box.setContent("html", function(){return this.getLayoutTemplate()});

And I do not have a getlayoutTemplate method - but nor does AI.UI.List ??