Symantec Encryption Desktop (formerly PGP Desktop) does not encrypt and decrypt e-mails when Microsoft Outlook accesses emails on the Zarafa mail-server through the Zarafa connector for MAPI.
While Microsoft Outlook indeed talks MAPI to the Zarafa Outlook Client, it does not use MAPI over the network interface. The Zarafa Outlook Client will connect over HTTP (on port 236) or HTTPS (on port 237) to the Zarafa server component for all its communications.
Symantec Encryption Desktop only detects e-mail streams via MAPI, IMAP, POP3, SMTP, and Notes. It does not detect e-mail streams via other protocols as what the Zarafa Outlook Client is using.
Symantec Encryption Desktop does not support the Zarafa Outlook Connector.
You can configure Outlook to either use IMAP or POP3, with SMTP to communicate with the Zarafa server.
The Zarafa Collaboration Platform is an open-source groupware platform that also offers an integration for Microsoft Outlook clients using the MAPI protocol.