Targetting problems

I am trying to do a little rollover effect in my animation. The animation (call it today.swf) is loaded into another animation using XML. Inside of today.swf, I have 3 buttons. When you rollover each one, they are supposed to change the alpha property of a movie clip (clip1, clip2, and clip3 for the three buttons). It works fine within today.swf but not when it is loaded into the other movie. I am guessing this is some _parent/.this stuff, but I can’t seem to make it work. Right now I have this on the buttons:

 
on (rollOver){
 setProperty(this.screen01, _alpha, "100");
}
on (rollOut){
 setProperty(this.screen01,_alpha,"0");
}

Any thoughts as to how to make this work?