No Glidepoint tapping after 2.0 upgrade

[fredmart@employees.org (Fred Martin)]

I have recently upgraded my system to Debian 2.0 (r2) and
I can no longer get Glidepoint tapping (button 4) in
X-Windows.  I'm using xserver-s3 which reports that it
is XFree86 Version 3.3.2.3.  I've have
Section "Pointer"
  Protocol "GlidePoint"
  Device "/dev/ttyS0"
EndSection
in my XF86Config file, but when I startx, xmodmap -pp
only reports 3 buttons, and xev shows no events for
tapping.

I still have my 1.3.1 (bo) install on another
partition which has XFree86 Version 3.3, and tapping
has been working just fine there.  xmodmap -pp reports
4 buttons, and tapping reports button 4 events in xev
(normally xmodmapped to button 1).

I just cannot figure out what I'm missing here or what
else I had to do to get this working in bo.  I've
been happily using Debian Linux since buzz, and thus
far I've found answers to any problems I've had
searching the docs and e-mail archives.  But I'm
just not finding anything on this one.

Fred Martin