Additional Considerations

If you need to archive message tracking data with the message copies, select Enable message tracking on the General property page of the MTA Site Configuration object. Then copy the daily log files from the Exchsrvr\Tracking.log directory to your archive location.
Do not disable per-domain-bilateral-info if you are using message journaling. Per-domain-bilateral-info is disabled when the following registry key it set to 1.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
\MSExchangeMTA\Parameters\Do not generate Bilateral Info
For more information, see Microsoft Knowledge Base article Q157358. Knowledge Base articles are available from the Microsoft support Web site at http://www.microsoft.com/support.
Message journaling can only capture messages that pass through the Microsoft Exchange Server MTA. If a user connects to an external mail server using a client that submits e-mail through SMTP (POP3 and IMAP4 clients) without passing through Microsoft Exchange Server, the messages will not be captured. Likewise, messages sent using other mail systems such as PC Mail that do not pass through a Microsoft Exchange Server cannot be captured, even if the other mail system has a connector to a Microsoft Exchange Server computer.