centrare img in movieclip

[crescenzo]

var mcl:MovieClipLoader = new MovieClipLoader(); 
var mclL:Object = new Object(); 
mclL.onLoadProgress = function(target, loaded, total) { 
    loader.percent.text = Math.round((loaded/total)*100)+"%"; 
}; 
mclL.onLoadInit = function(target) { 
    loader._visible = false; 
    loader.percent.text = ""; 
//lo devi centrare qua dopo che è stato caricato
target._x = (Stage.width/2)-target._width; 
target._y = (Stage.height/2)-target._height;

}; 
mcl.addListener(mclL); 
mcl.loadClip("img1.jpg", mc);