I have email enabled document libraries in Moss2007 that work fine when clients manually type in the email adddress in Outlook or if they create a contact in Outlook.
The contact/address that gets created in the Global Address List will not work though. It will pull up when addreessing but the message bounces back with an "Email address not found". If you double click on the contact in the address bar there is no email address which would explain the bounce. In the Exchange Contact properties there is an "External Email Address" entry with the correct document library email address. After manaully creating an SMTP email address with the same email address, the contact that pulls up when addressing a new message now has an SMTP address and no bounch occurs but the message is not arriving in the document library.
To recap, when manualy entering the email address of the document libary in Outlook, or by entering the document library as an outlook contact, messages are deliverd to the document libary just fine. Only the contact/exchange contact that gets created by the document library doesn't work.