How do I assign a mouseclick event Listener to a simplebutton already nested in a movie clip when it's dropped on stage?

Question

I'm trying to assign a mouseclick event listener to a simplebutton nested within a movie clip's later frames, starting at frame 2 and up. This card, however, is not added to my game until later, and when the player clicks on it/turns it over.
There are four files involved in this program:
#1 The main actionscript file, which corresponds to
#2 my dreamQuester .fla file.
#3 my artifactCard file movieClip's corresponding .as file,
#4 my combo1.as file corresponding to a an instance of a simpleButton named combo1 that is already
nested --and this instance is already named-- inside/as a child of said artifactCard movieclip.
What I've done so far isn't working:
In my main dreamQuester.as file, when a player clicks on an artifactCard, its MOUSE_DOWN event
listener takes them to this function (clickArtCard), where the trouble is at:
// player clicked on the artC card--which is a child of posArt1 on stage--to turn card over:
        function clickArtCard(a_event:MouseEvent) {
            var thisArtCard:artifactCard = (a_event.target as artifactCard);
            thisArtCard.gotoAndStop(unclickedArt1);  // go to frame number of artifact
                                // card where combo1 button is.
            thisArtCard.removeEventListener(MouseEvent.CLICK,clickArtCard);
            thisArtCard.buttonMode = false;
            trace("combo1.combo is:" + combo1.combo);
            trace("posArt1.artC.combo1 is:" + posArt1.artC.combo1);
            posArt1.artC.combo1.addEventListener(MouseEvent.MOUSE_DOWN, comboClickedWHO);
when the artC card--the static public instance of artifactCard--is clicked, it only gets to the
trace("posArt1.artC.combo1 is:" + posArt1.artC.combo1); which returns this error message:  
TypeError: Error #1010: A term is undefined and has no properties.
    at MethodInfo-61()
So do how would I declare a static public variable of this simpleButton at the start of my main .as
file to make it defined to get a mouseDown actionListener into my pre-existing-and-named-instance
combo1 simpleButton?
perhaps there is a way, while the debug movie program is running, to click on the simpleButton and see exactly
what it's parent heirarchy is, to see the name of all parents above the simpleButton incase they are
different then what I think?
(just in case, I was hoping to squeeze a zip file containing these files to be less than 9MB incase someone was willing to look at my files to see what I've done so far, but 9 megs is just too big! even though all graphics I've imported where turned into vector graphics with trace bitmap. I wish there was a way to check the file size of each symbol in Flash CS4, here...)
Thank you so much for any help!
~Ethan

Answer 1

Just use a
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
function keyPressed(event:KeyboardEvent):void {
     //trace(event.keyCode);
     if(event.keyCode == ???){
          // play the sound
Where I show the "???" you would replace with the keyCode for the key you want pressed for that sound.  To determine the keyCode you can use the trace line that I have commented out.
Note that when testing in Flash you often need to disable the keyboard shortcuts in the Flash Player in order to be able to use alot of the keys.  You will find this option in the Control menu options in the player.