After checking the issue, it seems this is a general Exchange related issue. As this forum focuses on Windows SteadyState specific issues, this inquiry would best be posted to Exchange forum:
http://forums.microsoft.com/TechNet/ShowPost.aspx?siteid=17&PostID=3950254
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the newsgroups regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.