smail instead of sendmail

My .procmailrc uses this:

(formail -r ; ls -l $MAILSERVER )|$SENDMAIL -oi -t

but sendmail is really smail.

This is causing problems because the 'From:' line on my  
auto-replies is wrong:

From: Timothy Luoma 
<luomat%nerc1(_dot_)Princeton(_dot_)EDU(_at_)Princeton(_dot_)EDU>
instead of:

From: Timothy Luoma <luomat(_at_)nerc1(_dot_)nerc(_dot_)com>
or
From: Timothy Luoma <luomat(_at_)nerc1(_dot_)nerc(_dot_)com>

Anyone familiar enough with sendmail and smail to know what I should do?

Thanks!

TjL