Windows Media Center Requires an "8-Digit Setup Key"

I am trying to setup my WD TV Live as a Windows Media Center “Extender”.  When trying to do this, Windows Media Center asks for an “8-Digit Setup Key”.  Can anyone tell me where to locate this key on my WD TV Live?  Thanks.

They aren’t Media Center Extenders – there is no provided key.

Other than a Xbox, as far as I can tell, the *only* “Media Center Extender” that was still available and not discontinued (and this information is over a year old) is/was the DLink DSM-750.