hi BB.
It does not matter at all, where in the world you fly: There are several JAR-OPS operators in Latin America and the Caribben, and all these will keep your JAR licence current. Also, most of the European Agencies will keep the licence current, if outside JAA territory while in their employ.
Mostly, you will not do another full licence (which often is based on some old national European licnece), which would involve passing several tough subjects again, but you'd get a validation instead, sometimes just over the counter, sometimes you'll have to write Airlaw.
A JAR TRE is necessary and also a JAR approved simulator to keep your licence current.
regards, IP