Thanks for the feedback. You were spot on:
Outlook on Exchange server is correct.
Outgoing Mail Format was set to Rich Text. [default]
Internet Mail [I assume this means to a recipient NOT on our exchange server?] was set to Convert Rich Text to HTML.
I changed Outgoing Mail Format to Plain Text and now everything’s jake.
DrewFrom: Eric Eisenhart [mailto:email@example.com]
Sent: Tuesday, October 22, 2002 4:34 PM
Subject: Re: [rt-users] Strange AutoReply Behavior - treatment of
<mailto:firstname.lastname@example.org om? In sigFile?