Reflection Effect using CS3?

How can I perform (what used to be) a simple reflection effect to a movieClip in Flash CS3?

Is there a tutorial anywhere that shows how this is done? I have heard you have to use addChild(); instead of setMask(); - do you use addChild() exactly the same way you would use the setMask() now?

Someone please help or show me a good tutorial to do this!

Thanks!