How can I refer to loading movie?

“For display objects in loaded SWF files, root references the main timeline of that SWF file”.

I have loaded a .swf file into a movie clip of another .swf.

var ldr:Loader = new Loader();
ldr.load(new URLRequest(“test.swf”));
addChild(ldr);

This code is inside the movie clip. I have a dynamic text field named messageText in the main timeline of the loading movie. How can I refer to messageText from the loaded movie? If I use command root.messageText.text = “something” in the loaded movie it refers to the root of that movie. Is it possible to refer to the messageText of the loading movie (other root)?