currently, at least on windows, zabbix frontend always uses the "default" locale. it should be determined whether it's useful to try more specific locale first and fallback to the "default" one aftwerwards (for example, try "portuguese-brazil" first and fallback to "portuguese")

further reading :

windows setlocale documentation : http://msdn.microsoft.com/en-us/library/x99tb11d(v=vs.80).aspx
windows supported language list : http://msdn.microsoft.com/en-us/library/39cwe7zf(vs.71).aspx