Please see the following post that i started.http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/56717f7b-9638-4e0d-b22c-f1031c1d021cI have verified that this is indeed a problem when I have the ASA in place. Bypassing the ASA...

Did you ever find a solution to why the ASA is doing this? Im having the same problem