Some of you have been able to use my basic quick and dirty walkthrough for publishing Exchange2010 with TMG.
Good news! there is a very detailed whitepaper from Greg Taylor that goes in to much more detail.
Here is a link to the whitepaper as well as the EHLO article.
That being said I am still working on the:
Internet –> TMG FE –> TMG BE –> Exchange Publishing rules and hopefully will have the walkthrough done by the 23rd.