Stage 2 proposal for review - "impose-role" attribute

Hi Carsten and Gershon (and anyone else who wants to join in the stage 2 review), I've attached the stage 2 proposal for the "Impose role" use case.
Please let me know if you have any questions or suggested updates.
Thanks, Robert Attachment: Issue670-ImposeRole.pdf Description: Issue670-ImposeRole.pdf