Preloading problem

1

the trace statments
trace(total);
trace(loaded);
are only displayed once the loading progress is complete…
how can i make them display when the clip is being loaded



public function App (mc : MovieClip) : void
        {
            this._mc = mc;
            loadXML();
        }


        private function loadXML () : void
        {
            try
            {

                loader = new URLLoader(new URLRequest("img.xml"));
                loader.addEventListener(Event.COMPLETE, createHolders);    
                loader.addEventListener(ProgressEvent.PROGRESS, preLoader);    
            }
            catch(Err : Error)
            {
                trace("Error " + Err.message);
            }
        }

        private function preLoader (e : ProgressEvent) : void
        {
            total = e.bytesTotal;
            loaded = e.bytesLoaded;     
            trace(total);
            trace(loaded);
        }