Exchange 2013 ARR Autodiscover issue

Hello Everyone,

I have setup Exchange 2013 and using ARR IIS as a reverse proxy from the below article.

http://blogs.technet.com/b/exchange/archive/2013/07/19/reverse-proxy-for-exchange-server-2013-using-iis-arr-part-1.aspx

However, I am finding my audodiscover is not working when I route my traffice through my reverse proxy.  I have double checked my URL Rewrite rules as well as my Server Farm settings and both match the article. 

When I run the setup in Outlook is takes awhile on the Configuring stage then it throws an eorror "The action cannot be completed.  The connection to MS Exchange is unavailable.  Outlook must be online or connected to complete this action."

If I change my DNS to point directly to my CAS server then autodiscover works fine.  It appears to be an issue with my ARR setup.

Anyone else having this issue with ARR IIS and Exchange?

Thanks...