Using Tween Class in an externally loaded movie

If the tween class is imported into a main movie, and I use loadMovie to load an external movie into the main movie, is there a way to reference to the tween class in the main movie for use in the external movie? Kinda confusing, right…

I import this in the main movie:

 
import mx.transitions.Tween;
import mx.transitions.easing.*;

And I have tried to access the tween class in the main movie from the externally loaded movie to fade a movieclip in it with instance name “fade”… I tried the following methods, but none of them work:

 
new Tween(fade, "_alpha", _root.Strong.easeInOut, 100, 0, 2, true);
new Tween(_root.externalmovie.fade, "_alpha", _root.Strong.easeInOut, 100, 0, 2, true);
new Tween(_root.externalmovie.fade, "_alpha", Strong.easeInOut, 100, 0, 2, true);
new Tween(_root.externalmovie.fade, "_alpha", mx.transitions.easing.Strong.easeInOut, 100, 0, 2, true);

I know I could just import the Tween class into the external movie & use it that way, but I’m just trying to figure out why I can’t use it since it was already imported into the main movie… any suggestions would be appreciated!