TidPOP3 and " Content-Type: message/rfc822 "

Forgive my ignorance,

I have a MIME message, which as  one of it's several parts has an
embedded "Content-Type: message/rfc822" message. How do
I extract the inner embedded message d so that it can be processed
as a TidMessage and it's subsequent embedded attachment

( ie: Content-Type: application/octet-stream;
Content-Transfer-Encoding: quoted-printable
Content-Disposition: attachment;
        filename="XXX.dbf" ) may be saved?