ActionScript 3.0 :: Using State Pattern To Show An Image Pre-loader?

My app uses a MVC pattern to display images - obviously they need to get loaded first, so...

I have two states ContentFull and ContentEmpty these are both typed as ContentState.

both implement IContentState which has the following function:

function getContent(model:ISIModel):Sprite

In the view, VContentView I have the following:

override public function update(event:Event = null):void
{
if(icontent!=null){this.removeContentChild()}; //not really necessary, but there to make sure
icontent = model.getContent();

[Code].....

So the problem is - When the image is loaded - everything is perfect, when the image is loading, and ContentEmpty.getContent() is called the percentage value calculated from bytesLoaded/bytesTotal is initially set at 0 and displays just fine, but... it never changes to 5%, 10% etc...

I have put trace statements to track it incrementing, which it does just fine, I have followed it around in debug (using the Flash CS4 IDE), I have nuked the entire display list and then added everything back, I have instantiated a new counter text object as a sprite in a separate class, but it stubbornly refuses to do anything other than sit at 0 until the image loads and then the ContentState is set to ContentFull and the image displays.