[flexcoders] setting fillcolor with actionscript and stylename

[netdeep]

I have a panel component:

<mx:Panel id="panel" styleName="gradientBgrd">
<mx:Style>
        .gradientBgrd { 
                borderStyle: applicationControlBar; 
        }       
</mx:Style>

And I want to update the fillColors in actionscript:

panel.setStyle("fillColors", [0xFF0000, 0x00FFFF]);

but this doesn't work.  What is the proper syntax?

Thanks.