Orbeon - Access to created and last_modified within form

How do I get access (i.e. set a text bo开发者_运维问答x) to the created and last_modified values?

The created and last modified date is returned by the search operation of the persistence REST API, so this information can be displayed in the summary page. However, it is not available as part of the form data, and at this point you can't access it from within a form, when the form is displayed.