I am the engineer for a major health fund in Adelaide, Australia. We recently implemented a change from Exchange Server 2000 to Exchange Server 2007 in a Clustered configuration.
Everything works fine except that we receive messages from a government department carrying attachments which are an encrypted email message which we extract from the message and then import into our Health Fund software which decrypts the message and extracts the statement or whatever and processes it. THis process works fine where the messages are brought in from Exchange 2000, but when the receiving mailbox is moved to Exchange 2007, the attachments are no longer usable. The problem appears to be that the encapsulating message has both its content type and the description of the content changed during the storage process, and the attachment then becomes contaminated by the rest of the message header. The fault is reproducable, but even Microsoft have been unable to show how we can receive these .eml attachments unchanged.
Since the original post, while working through the problem, we have found that the problem lies in the storage conversion onto the CCR Mailbox Server array, and there is an as-yet unreleased hotfix which addresses a similar issue. We are waiting to get it to see if it fixes the problem.
Why MS wants to mess with the contents of an attachment defies logic to me. Anyone have any thoughts?