The settings app just shows you all of the locales that are available in the platform resources. Adding strings for a new locale should automatically have those shown in settings.
You tell the build system which locale resources to include when it does the build... unfortunately I can't help you on that part, but maybe someone else can.
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Dianne Hackborn
Android framework engineer
hac...@android.comNote: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them.