1. Read MailItem.MAPIOBJECT property
2. QI it for IMessage Extended MAPI interface
3. Call IMessage::GetIDsFromNames() passing the appropriate GUID and id
4. "Or" the retirned tag with the appropriate type (PT_STRING8)
5. Use Imessage::SetProps or HrSetOneProp to set the property with tag from
#4.

Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool

"Tom at GSD" wrote in message
...
Hi,

I have developed an ATL/C++ add-in that I want to add a header item to a
_MailItem before I forward the email. The idea is that I take an item out
of
the inbox, modify the header and then forward it to another email address.
I
see there are Redemption examples; but I do not want to use the redemption
libraries. Is there an extended MAPI example that will show me how to
accomplish this? I do not want to use any third party utilities. I have
looked for examples on the web but I do not see any.

Thanks,
Tom -