using procmail to just send mail

Hello,

   I am currently using MMDF as my MTA.  Here is what I would like to
accomplish:

       When I send mail from my account, I would like the Sender: field
        to be munged and replaced.  For example: If I send a message from
        my current system called system1.com to someone else, like:

           mail joeblow(_at_)foo(_dot_)com

       I would like joeblow to receive the message with my
        Sender: field changed to valcourt(_at_)bar(_dot_)org instead of
        valcourt(_at_)system1(_dot_)com(_dot_)

------------------------------

To: joeblow(_at_)foo(_dot_)com
Subject: Autoreply from Manager
From: valcourt(_at_)bar(_dot_)org
Date: Tue, 4 Jun 96 9:49:58 EDT
Sender: valcourt(_at_)system1(_dot_)com            <- I would like this to be 
munged

                                                        too
------------------------------



        Also, I am sending this mail after receiving an incoming msg that
starts procmail.  Can I use the functions of procmail on outbound messages
(i.e. I did not get an inbound message to kick off procmail)?

  thanks,
    ken