[Kikasso]

var my_x:X = X(attachMovie( linkage_id, depth ));

class X extends MovieClip {
private var container_mc:MovieClip;
public function X() {
 super();
}
public function onEnterFrame() {
 trace("yes");
 container_mc._x++;
}
public function load_X(URL:String):Void {
 container_mc.loadMovie(URL);
}
}

container_mc должен быть в клипе.