What's the best way to embed custom schema like HR-XML into XMP?

The specs (Part 2) mentioned that you can create custom name spaces. I'm looking to embed HR-XML into XMP.

We are looking to embed personal meta data into a PDF resume to improve parsability. We would prefer to stick to the existing standard (HR-XML) for formatting resume data. Are there any examples or code samples of embedding custom XML schema into a XMP stream? The documentation on this area is pretty thin.

Thanks