Delegate.Create for an mc inside a class [DEADLINE] pls help

[flashDeveloper]

import mx.events.EventDispatcher;
import mx.utils.Delegate;

class main_movie extends MovieClip
{
    public var pbSend:Button;
    public var my_mc:MovieClip;
    public var my_button:MovieClip;

    // constructor
    public function main_movie()
    {
        super();
        EventDispatcher.initialize(this);
        my_mc = attachMovie ("my_mc", "my_mc", getNextHighestDepth(), {_x :100, _y:50} );
        my_button = attachMovie ("my_button", "my_button", getNextHighestDepth(), {_x :100, _y:50} );
        my_button._x = 100;

        // I want to avoid doing this function here..
        /*this.onLoad = function()
        {
            // this is the only line that works and it does add the event.
            pbSend.addEventListener("click", Delegate.create(this, checkFields));

            // doesn't work
            my_mc.addEventListener("onRelease", Delegate.create(this, checkFields));

            // doesn't work
            my_button.addEventListener("onRelease", Delegate.create(this, checkFields));
        }*/


        //this["my_mc"].addEventListener("click", Delegate.create(this, checkFields));
    }

    // I would rather do it here...
    private function onLoad ()
    {
        // doesn't work, this line doesn't work in the onLoad function if its placed here !
        //pbSend.addEventListener("click", Delegate.create(this, checkFields));

        // doesn't work This is the most important one I really need to get it to work
        my_mc.addEventListener("onRelease", Delegate.create(this, checkFields));

        // doesn't work
        my_button.addEventListener("onRelease", Delegate.create(this, checkFields));
    }

    private function checkFields():Void
    {
            trace("check");
    }
} 

Hi I need help, all I want to do is to create an onRelease event for the my_mc
clip which is being attached within the main_movie class.

it works for the button component but not for the mc clip... please advice

thanks