From: Jason Swager Jason on
This question originates from from the Visual Studio Tools for Office Forum,
but the current theory is that it has nothing to do with the Tools, and
everything to do with just plain Outlook. Reference to the original message:

Summary: I'm using Outlook 2007 with an IMAP/SMTP account. When we send an
email that has an attached email with a custom header, the attached email
looses its custom headers while Outlook is sending the message to the SMTP

In our Inbox is a message with custom header; this was confirmed via the
Message Options dialog box, Internet Headers. While viewing the message,
select the Other Actions, Forward as Attachment. This creates a new message
that has the original message as an attachment. If I view that attachment, I
can check the Message Options, Internet Headers and still see the custom
header. If I send the new message (the one generated by Forward as
Attachment) and check the message when it is received, there is still an
attached email message. But when I view the Message Options, Internet
Headers of the attached message, it no longer has the customer headers.

I confirmed that the headers were not being sent by using WireShark and
sniffing the SMTP traffic. It also shows that the attached message does not
have the customer headers.

How do I preserve the custom headers of the attached email message? ZIPping
an exported MSG file and unzipping on the receiving side is NOT an option.