Hello,
could anyone tell me excactly how Microsoft Outlook 2003 handles the
MIME mediatype "message/rfc822"? The reason I am asking is because I
am currently working on a gateway to convert mail from a custom format
to the rfc2822/rfc2045-2049 specification(s).

In this custom format, it is entirely possible for a mail message to
have whole mail messages attached. It seemed like this would be easily
solved by using the message/rfc822-type to include the entire mail,
but this turned out to be a problem if the attatched mail was itself a
MIME multipart-message. In that case, Outlook simply refuses to list
the incoming mail message at all. Now this was frustrating as,
according to the spec, a message/rfc822-object is allowed to be a
"full blown" MIME-message despite what the name might suggest. To make
sure there was nothing wrong with the generated mail message, I also
tried importing it into several other clients with success, so it
seems like this problem is Outlook-related. An example of such a
message is included below.

I would appreciate any help or suggestions with this, as I don't
really know how to proceed.

#Start mail-example (headers removed/boundaries renamed to slightly
enhance
readability):

Priority: normal
To:
From:
Subject: Fwd: Attached mail
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="outer_boundary"

This is a multi-part message in MIME format.

--outer_boundary
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

Bp forwarded mail

--outer_boundary
Content-Type: message/rfc822
Content-Transfer-Encoding: 7bit

To:
From:
Subject: Attached mail
Content-Type: multipart/mixed;
boundary="inner_boundary"
MIME-Version: 1.0

This is a multi-part message in MIME format.

--inner_boundary
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

Bodypart 1, attached mail

--inner_boundary
Content-Type: text/plain
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

Bodypart 2, attached mail

--inner_boundary--

--outer_boundary--

#End mail-example