A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Enhancements to Internet email to support diverse service environments Working Group of the IETF.
Abstract: “This specifications defines a method for IMAP4 clients to retrieve message content via an external (i.e. non-IMAP) protocol mechanism.”
http://www.ietf.org/internet-drafts/draft-ietf-lemonade-imap-channel-01.txt