Accessing selected ViewStack container's properties/methods

Question

I have an Air application that has in it:

<mx:VBox>     
    <mx:ViewStack id="vs">
        <mycomp:Elist id="elist"/>
        <mycomp:Achart id="achart"/>
        <mycomp:Txy id="txy"/>
    </mx:Viewstack>
    <mx:Text id="info" htmlText="{compinfo}"/>
</mx:VBox>

Where each "mycomp" is a MXML component I created. Each component is different but each contain a property: public var infotxt:String;

I wish to set the text of the "info" text component to the value of the selected mycomp. A timer changes the vs.selectedIndex periodically.

I've tried something like this in the timer event handler:

compinfo = vs.selectedChild.infotxt;

which yields me an "access of possibly undefined property infotxt through a reference with static type mx.core:Container.

What is the right way of doing this? I know I could move the text component to the child, but it seems like there should be a way of doing this.

Thanks in advance... TB