Comment 50 for bug 116193

This should be fixed in hardy's version, since one of the merged changes from Debian was:

tzdata (2007f-5) unstable; urgency=medium

  * Handle three-level timezones (including Argentina) in debconf
    selection, as well as converting Argentine compatibility zones
    to their three-level counterparts. closes: #426914.
  * debian/po/en.po: updates for "new" zones.

I'll look into backporting this to gutsy.