Simplest way to "redirect" an email message

My email program has a "redirect" function that re-sends an email
message to someone else but doesn't modify the body and headers - so
the resent message appears just like it did the first time. If I
receive a message and redirect it to my friend Joe, he still sees "To:
Joshua Baer" in the headers.

Any idea what is the simplest way to do this with ROR? I was trying to
use Net::SMTP but while it works for simple text messages it is
failing on more complex multipart MIME messages.

from = from@example.com
to = to@example.com
mail = tmail.to_s
Net::SMTP.start(SMTP_server, 25) do |smtp|
      smtp.send_message mail, from, to
end

Is this the right approach if I'm starting with an mbox style message
parsed out with RMail::mailbox::MBoxReader?

Thanks!

~Josh