I thought I could change the Boolean true/false value, but it's not working. How do I get this to hush, until the button is pressed?

import flash.media.Sound;
import flash.media.SoundChannel;

var soundOn:Boolean = true; //music is ON when we start
var myToons:TitleMusic = new TitleMusic();
var myChannel:SoundChannel = myToons.play(0,1000); // endless loop, in effect
var myTransform:SoundTransform;

mySoundButton.addEventListener(MouseEvent.CLICK,toggleSound);
mySoundButton.buttonMode = true;
mySoundButton.mouseChildren = false;


function toggleSound(e:MouseEvent)
{
    if(soundOn)
    {
        // turn sound off
        myTransform = new SoundTransform();
        myTransform.volume = 0; // silent
        myChannel.soundTransform = myTransform;
        soundOn = false;
        mySoundButton.myButtonText.text = "click to turn sound ON";
    }
    else // sound is off
    {
        // turn sound on
        myTransform = new SoundTransform();
        myTransform.volume = 1; // full volume
        myChannel.soundTransform = myTransform;
        soundOn = true;
        mySoundButton.myButtonText.text = "click to turn sound OFF";
    }

}