Curse-Breakers usually work for Gringotts but can be affiliated with other institutions like the Ministry. I don't know if anyone has ever actually RPed a curse-breaking mission on HO before, but you could talk to the people who teach the curse-breaker courses and see what you can come up with and start doing some expeditions or something. The reason you probably don't see it around much outside of the Ministry is because we've had trouble keeping an active Gringotts and banking system going on HO, and for some reason, the employment didn't seem to go past goblins. But that's something that's currently being worked on.
As for posting abroad in other places, you could ask Ying to consider making another forum somewhere that's like a catch-all for the rest of the world locations, like "Everywhere Else" or something.
(Edit: We now have a forum and separate category called "Foreign Lands" where you can post in places that are not the UK, Sweden, or France!)
Here is more information about Curse-Breakers from HP Wiki that you might consider reading.
A Curse-Breaker is a profession at the wizard's bank Gringotts, in which a wizard or witch disables or counters curses in ancient tombs or other historical sites, in order to bring back gold to Gringotts. It is speculated that Curse-Breakers are almost the equivalent of Muggle archaeologists.
It is said to be a very dangerous and serious profession, in which a wizard or witch could be killed as a result of an old curse, jinx, or hex. An O.W.L. in Arithmancy is required, as some banking and transacting will be done. Also, presumably, N.E.W.Ts in Defence Against the Dark Arts, Potions, Transfiguration, and Charms would be necessary, given the dangerous aspects of the job, as well as one in Ancient Runes. (However, this is merely a speculation).
Curse-Breakers do not have any known uniform; the Goblins running Gringotts generally do not care what the Curse-Breakers look like in terms of appearance or dress, as long as they bring much treasure back to the bank. Curse-Breakers are known to operate in Egypt and other areas of ancient magical importance.