Getting OOXML of a header / footer

Hi,
I would like to be able to get the underlying OOXML of a header / footer from a docx file. I can use the Node.ToString(SaveFormat.Html) to get HTML but would prefer OOXML. I need to store the header/footer OOXML separate so users can select the header/footer they want during document construction.
Thanks!

@cbowman I am afraid there is no way to get OOXML of a header / footer separately from the whole document. As a workaround, you can store header / footer in a separate documents and save these documents as OOXML.