[flexcoders] Actionscript question

[elevight]

I have created an empty actionscript class, and I'm trying to use 
metadata to change the background color:

package 
{
        [SWF(backgroundColor="#ff0000")]

        import flash.display.Sprite;
        
        public class SampleClass extends Sprite
        {
                public function SampleClass()
                {
                }
        }
}

But the background color is not changing to red. Can anybody see what 
I'm doing wrong?

Thanks.