Translating from one of Mariano Absatz's references
http://www.lanacion.com.ar/04/06/10/de_609078.asp (starting from the eighth full paragraph):
"The time change in Tierra del Fuego was a conflicted decision from the start. The government had decreed that the measure would take effect on June 1, but a normative error forced the new time to begin three days earlier, from a Saturday to a Sunday, which confused the public, who inundated the Fire Department, Civil Defense, and Police detachments with calls seeking the official time. "Thus, Tierra del Fuego, which had subordinated its adherence to the time change to the decision of Chubut and Santa Cruz, wound up changing ahead of its neighbors." Our understanding was that the change was originally scheduled to take place on June 1 at 00:00 in Chubut, Santa Cruz, Tierra del Fuego (and some other provinces). Sunday was May 30, only two days earlier. So the article contains a contradiction. I would give more credence to the Saturday/Sunday date than the "three days earlier" phrase, and conclude that Tierra del Fuego set its clocks back at 2004-05-30 00:00. If this is correct, an America/Ushuaia zone will have to be created to accommodate this time change. Gwillim Law