XADM: Display Name Missing for RFC 822 "Group:;" Address

Microsoft Exchange Server versions 4.0 and 5.0 do not handle the Display Name (DN) correctly in messages received from the Internet that were sent to a Distribution List (DL) using the RFC 822 addressing form of:

The addressing option defined by RFC 822 section 6.2.6 states that users may be able to address messages to a group or DL in the form:

Notice that no individual members were listed in the address above. When a message sent externally to a DL in this form arrives in Microsoft Exchange Server, the DN is not handled correctly. In Microsoft Exchange Server version 4.0, users will see the following:

In Microsoft Exchange Server version 5.0, the DN will be blank. The messages will still be delivered to the recipients though they will be unable to reply to the DL.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server, version 5.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
Customers who experience this problem on Microsoft Exchange Server version 4.0 will need to upgrade to Microsoft Exchange Server version 5.0 and Microsoft Exchange Server Service Pack 1 (SP1) and install the post SP1 hotfix in order to resolve this issue.