Controlling movie clips from different functions

lets say this is what i have:


class thisClass {
    public function thisClass(){
        // do nothing
    }

    public function loadthisClip(where:Stage){
        var mc:MovieClip = new MovieClip();
        var mc_txt:TextField = new TextField;
        mc_txt.text = "click me";
        where.addChild(mc);
        mc.addChild(mc_txt);
    }

    public function controlthatClip(){
        // how would I control mc from here??
        // for example, this doesn't work:
        trace(mc);
        // or this :
        trace(MovieClip(mc));
    }
}

I’m just getting into AS3 and using class’ and stuff… Waaaay to used to relying on the timeline and paths for controlling stuff. Thanks in advance for the help…