[flexcoders] ComboBox.selectedItem within a Repeater

[t8.chad]

I have a ComboBox within a repeater and I need to get the selected item
of the ComboBox.  The problem is that the id of the ComboBox is really a
pointer to an array of ComboBoxs within the Repeater.

<mx:TabNavigator>
     <mx:Repeater id="rp_brands">
         <mx:ComboBox id="cb_sports"
dataProvider="{rp_brands.currentItem.sports"/>
         <mx:Button label="TEST" click="trace('selected sport:
'+cb_sports.selectedItem)"/>
     >
>

cb_sports.selectedItem is a null reference, which makes sense since the
cb_sports ComboBox is an array of ComboBoxes within the Repeater.  How
can I get the selectedItem of the ComboBox?  I cannot use the rp_brands
Repeater's currentItem or currentIndex property as an index to the
cb_sports ComboBox Array because this is being executed in an event
("Repeater is not executing" error).

Thanks.