How about looking at Email::Outlook::Message. (Upon further inspection I see that you want to create an .msg file. Still, this module might be helpful since it shows how to parse one.)

In reply to Re: Turn an rfc/822 type MIME part into an Outlook .msg file? by pc88mxer
in thread Turn an rfc/822 type MIME part into an Outlook .msg file? by blahblahblah

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