PhotoGallery&Dynamic Text( flash cs4)

Question

I have a photo gallery but what i want to do is when i click on a photo i want the name of that photo to be shown in a dynamic text field. pls help because i am beating my brain over it

 import fl.containers.UILoader;
import caurina.transitions.*;

//---------loading the external xml file-------
var urlRequest:URLRequest=new URLRequest("pics.xml");
var urlLoader:URLLoader = new URLLoader();
var myXML:XML = new XML();
var xmlList:XMLList;
myXML.ignoreWhitespace=true;
urlLoader.addEventListener(Event.COMPLETE,fileLoaded);
urlLoader.load(urlRequest);
//--------holds the paths to the thumbnails-------
var arrayURL:Array = new Array();
//--------holds the paths to the big photos-------
var arrayName:Array = new Array();
//--------holds the thumbnail objects-------
var holderArray:Array = new Array();
//--------represents the number of collumns-------
var nrColumns:uint=4;
//-------represents the container of our gallery
var sprite:Sprite = new Sprite();
addChild(sprite);
var thumb:Thumbnail;
//-------- the thumbnails container-------
var thumbsHolder:Sprite = new Sprite();
sprite.addChild(thumbsHolder);
//-------- the photoLoader container-------
var loaderHolder:Sprite = new Sprite();
loaderHolder.graphics.beginFill(0xffffff,1);
loaderHolder.graphics.drawRect(0,0,550,330);
loaderHolder.graphics.endFill();
loaderHolder.x=500;
loaderHolder.y=300;
sprite.addChild(loaderHolder);
//-------- loads the big photo-------
var photoLoader:UILoader = new UILoader();
photoLoader.width=550;
photoLoader.height=330;
photoLoader.y=0;
photoLoader.x=0;
photoLoader.buttonMode=true;
photoLoader.addEventListener(MouseEvent.CLICK,onClickBack);
loaderHolder.addChild(photoLoader);
loaderHolder.visible=false;

/* we loop through the xml file
populate the arrayURL, arrayName and position the thumbnalis*/
function fileLoaded(event:Event):void {
    myXML=XML(event.target.data);
    xmlList=myXML.children();
    for (var i:int=0; i

and the thumbnail class


 package {
    import flash.display.Sprite;
    import fl.containers.UILoader;
    import caurina.transitions.*;
    import flash.events.MouseEvent;

    public class Thumbnail extends Sprite {
        public var nume:String;
        public var url:String;
        private var id:int;
        private var loader:UILoader;

        function Thumbnail(source:String,itemNr:int,numeThumb:String):void {
            url = source;
            id = itemNr;
            this.nume = numeThumb;
            drawLoader();
            addEventListener(MouseEvent.MOUSE_OVER,onOver);
            addEventListener(MouseEvent.MOUSE_OUT,onOut);
            scaleThumb();
        }

        private function drawLoader():void {
            loader = new UILoader();
            loader.source = url;
            loader.mouseEnabled = false;
            loader.x = -50;
            loader.y = -50;
            addChild(loader);

        }
        private function onOver(event:MouseEvent):void {
            Tweener.addTween(this, {scaleX:1,scaleY:1, time:1, transition:"easeoutelastic"});
            Tweener.addTween(this, {alpha:1, time:1, transition:"easeoutelastic"});
        }
        private function onOut(event:MouseEvent):void {
            Tweener.addTween(this, {scaleX:.9,scaleY:.9, time:1, transition:"easeoutelastic"});
            Tweener.addTween(this, {alpha:.5, time:1, transition:"easeoutelastic"});
        }
        private function scaleThumb():void {
            this.scaleX = .9;
            this.scaleY = .9;
            this.alpha = .5;
        }
    }
}