Triggering events .as -> .fla

Hey everyone
A made a class to make thumbs from loaded images.
I add a listener to every thumb to trigger a event in the main swf.
Already found ‘dispatchEvent’
I can’t seen to find a way to see what thumb called the event.

I need this info to apply some tween’s to the thumb triggering the event

Here you have the code from the class

package classlibrary{

	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.display.Sprite;
	import flash.display.Bitmap;
	import flash.filters.DropShadowFilter;


	public class MenuBuilder extends Sprite {
		private var list:XML;
		private var _mytestvar:String;
		private var _thumb_mc:Sprite;
		private var _squar_mc:Sprite;
		private var _thumb_pm:Bitmap;
		private var dropShadow:DropShadowFilter;
		private var _thumbMenu_mc:Sprite = new Sprite();

		public function MenuBuilder (list,loader) {


			dropShadow = new DropShadowFilter(2.5,45,0x000000,0.3,2,2,1,1,true);

			var _Witdh:Number = 0;
			var _Xpos:Number = 0;

			for (var i:Number =0; i< list.foto.length(); i++) {


				_thumb_mc = new Sprite();
				_squar_mc = new Sprite();
				_thumb_pm = loader.getBitmap("x" + i);

				_squar_mc.graphics.beginFill (0xCCCCCC);
				_squar_mc.graphics.drawRoundRect (-15, -15, _thumb_pm.width+30, _thumb_pm.height+30, 20, 20);
				_squar_mc.graphics.endFill ();



				_thumb_pm.filters = [dropShadow];
				_thumb_mc.addChild (_thumb_pm);
				_thumb_mc.name = "x" + i;



				_thumb_mc.x = _Witdh + _Xpos + 10;
				_thumb_mc.scaleX = _thumb_mc.scaleY = 0.2;


				_Xpos = _thumb_mc.x;
				_Witdh = _thumb_mc.width;

				_thumbMenu_mc.y = 300;
				_thumbMenu_mc.x = 0;
				_thumbMenu_mc.name = 'thumbMenu'


				_thumb_mc.addChildAt (_squar_mc,0);
				_thumbMenu_mc.addChild (_thumb_mc);
				
				_thumb_mc.addEventListener (MouseEvent.CLICK, Click);
				_thumb_mc.addEventListener (MouseEvent.ROLL_OVER, Over);
				_thumb_mc.addEventListener (MouseEvent.ROLL_OUT, Out);
				 addChild ( _thumbMenu_mc);

			}
			
		}

		private function Click (event:MouseEvent):void {
			dispatchEvent (new Event ('Click'));
		}
		private function Over (event:MouseEvent):void {
			dispatchEvent (new Event ('Over'));
		}
		private function Out (event:MouseEvent):void {
			dispatchEvent (new Event ('Out'));
		}
	}
}

and here the code i have in my swf

function callBuilder ( e:Event):void {
	var thumbBuilder:MenuBuilder = new MenuBuilder(xmlData,loader);
	thumbBuilder.addEventListener ('Click', thumbClick);
	thumbBuilder.addEventListener ('Over', thumbOver);
	thumbBuilder.addEventListener ('Out', thumbOut);
	addChild (thumbBuilder);
}

function thumbClick ( e:Event):void {
	trace (e.target.name);
}

function thumbOver ( e:Event):void {
	trace ("thumbOver");
}

function thumbOut ( e:Event):void {
	trace ("thumbOut");
}

Anyone any ideas ?