as3 accessing objects and vars on main timeline from class

I am trying to access vars, functions and objects hard coded on the main timeline from a class. The Objects, vars etc... are loaded when I call a function in the class like this:

Some code from main timeline:

import com.beauMoves;
var bm = new beauMoves();

bm.thisWorks();

and below is the class. But it is not accessing the main timeline. In this case I am trying to access a display object loaded from the lib and place on the timeline. The object is called "Beau" as you can see in the code below.

   package com {

import flash.display.MovieClip;
import com.*;   

public class beauMoves extends MovieClip 
{


        public function beauMoves()
        {
            // constructor code
            trace("BeauMoves");
        }

        public function thisWorks()
        {
            trace("Cool Beans! This one worked");
                    // THESE TWO LINES BELOW ARE NOT WORKING
            var main:MovieClip = MovieClip(this.parent);
            main.Beau.alpha = .3;

        }

}


}

Presuming the two lines below are on the main timeline, pass to beauMoves() this as a constructor argument:

import com.beauMoves;
var bm = new beauMoves( this );

Then in your beauMoves() class:

package com {

    import flash.display.MovieClip;
    import com.*;   

    public class beauMoves extends MovieClip 
    {
        private var _mainTimeline:MovieClip;

        public function beauMoves( mainTimeLine:MovieClip )
        {
            // constructor code
            trace("BeauMoves");

            _mainTimeline = mainTimeLine;
        }

        public function thisWorks()
        {
            trace("Cool Beans! This one worked");

            _mainTimeline.bm.alpha = .3;

        }

    }

}