I'm not entirely satisfied with the man page so a second opinion/help would be nice. I've actually added a "subsection" to the Hidden Service section in the manpage to explain a little bit how to configure client authorization.
Also, at this stage, we have no tools (not even "tor") to create client authorization keys and configuration thus why I haven't mentioned anything on how to create keys.
Trac: Status: new to needs_review Cc: N/Ato asn, haxxpop