[etc]

class MyLoader extends MovieClipLoader {

   private var _target:MovieClip;

   public function MyLoader(target_mc:MovieClip, name:String, depth:Number, url:String) {
      super();
      trace('MyLoader created');
      this._target = target_mc.createEmptyMovieClip(name, depth);
      this.loadClip(path, this._target);
   }
}

var loader:MyLoader = new MyLoader(this, 'target_mc', 10, 'test.swf');