@Lync and @Greg
well Lync brought to the point, and finally, I can agree with your article. If we see how Lync Setup for the external WebServies is required, we see (No Authentication, but Client may authenticate directly).
This is exactly what Greg refers to Exchange, so I need to ask everyone how wants TMG in front of Exchange, "why do you propose 2 different solution to a customer?", this is not logic.
So no since TMG is out of the picture, its clear what we need to do!
Btw, regarding a non authenticating RevProxy, there are hundreds of other solutions outside. I know this, since for Lync, I designed the right publishing way and user access.
I personally believe now, we are back on track and have the same solution for Lync and Exchange in case for pre-authentication.
Thanks Greg putting this clear.