I live in Argentina, and our DST rules change often. So often, that major OS' tend to ship with an old version of tzdata DBs.

In the past, I successfully updated the time zone databases in Tiger and Leopard. Today, however, when trying to update it in Snow Leopard, it did not work.

Not only it failed, but now even after I reverted my changes, there seems to be some "cache" where the time zone information was retained.

The files I updated (and reverted) are located at: /usr/share/zoneinfo and /usr/share/icu. To update those, I grabbed Apple's source code for ICU and recompiled it's database using the latest tzdata file (2010b). Then, I recompiled the tzinfo by running zic, and copied all the files to the system folders.

Does anyone have experience dealing with Snow Leopard's timezone DB and can help?

Thank you.