smail and US/Central time zone

[Douglas Bates <bates@stat.wisc.edu>]

I'm not sure whether this is a smail problem or a problem with another
program but headers from smail 3.2.0.102 are causing my mail to be
dropped by some spam filters.

I am in the US/Central time zone.  The timezone seems to be set correctly.
 bash-2.01$ cat /etc/timezone
 US/Central
 bash-2.01$ date
 Fri Nov  6 08:47:07 CST 1998
In the last couple of weeks mail through my Debian Linux systems has
suddenly started being dropped from some sites as spam.  The change
was probably at the time that we switched from Daylight Savings Time
to Standard Time.  Others tracked the mail problem to header lines like
 Received: by verdi.stat.wisc.edu
	 via sendmail from stdin
	 id <m0zbn53-0000ZAC@verdi.stat.wisc.edu> (Debian Smail3.2.0.102)
	 for bates; Fri, 6 Nov 1998 08:41:41 -0600 (EST) 

The last part of that header gives an illegal timezone.  It should be
-0600 (CST).  Unfortunately there are some notorious spam sites with
similar misconfigurations so mail originating on my computers is
dropped by some spam filters.

 bash-2.01$ ls -l /usr/sbin/sendmail
 lrwxrwxrwx   1 root     root            5 Nov  5 08:46 /usr/sbin/sendmail -> smail
 bash-2.01$ dpkg -s smail
 Package: smail
 Status: install ok installed
 Priority: important
 Section: mail
 Installed-Size: 1161
 Maintainer: Soenke Lange <soenke@escher.north.de>
 Version: 3.2.0.102-1
 ...

Are others in the US/Central time zone and using smail encountering this
problem?  Does anyone know how to fix it?