Region Tag in XMP Dev Kit

I try to use the Adobe's Extensible Metadata Platform  to insert a XMP tag into a jpeg file which describes the region and name of a face. I read that Adobe uses the standard with the namespace mwg-rs:Regions. Unfortunatly i am not able to find this namespace in the supplied dev-kit.

I am using the java dev kit btw.

Does anyone have an example how to insert such a tag (like on Extensible Metadata Platform - Wikipedia ) into a jpeg file with the devkit?