The issue is the way OWA 2010 handles requests for users on an Exchange 2007 mailbox server. If the users is on a 2007 sever in another AD site, the request is proxied to the 2007 CAS server in the other AD site. This works fine. The issue is when the user is on a 2007 mailbox server in the same AD site. The user is then redirected the 2007 CAS server in the same AD site. This redirection is not supported with our current web gateway\web proxy. Is there a way to force Exchange 2010 to proxy OWA request to the 2007 CAS server in the same AD site? Thank you for any and all information!

Short answer is, No. You need to setup an exception in your proxy to allow the redirection to take place or do what I did and migrate all of the users off of 2007 to 2010 and you wont have to deal with the redirection.