Hi Adam,
I think that you're digging yourself into a deeper hole, unless you really have some inside info. How about a shot of the left side of the DS lightbox (as you look from the back of the camera)? Like this:
Of course this might be a dummy sensor, or they might have not connected it, or even disabled it via firmware, but somehow I doubt that they'd do any of these.
FYI, the AF500FTZ does not have an Auto mode -- it's only automatic mode is TTL, and it works with the DS (as stated in the DS manual).
Why are you so resistant to this idea?
Scott