The "pap_AN" locale is present in glibc (/usr/share/i18n/locales/pap_AN, /usr/share/i18n/SUPPORTED). However, Netherlands Antilles was dissolved, and "AN" is not a part of ISO 3166 anymore (/usr/share/zoneinfo/iso3166.tab, sys-libs/timezone-data). According to setlocale(3), "territory is an ISO 3166 country code".
would you mind submitting this to: http://sourceware.org/bugzilla/
and official supporting (i.e. gov't) documentation would be useful too
thanks! we'll look into this upstream.