Footnote a on page 101 says that "This [SOAP] Fault is combined with an ebMS error message (eb:Messaging/eb:SignalMessage/eb:Error) unless it is generated by the Security or Reliability module."
This suggest that errors that occur in the Security or Reliability module will not be reported by an ebMS error message. Sections 6.7.2 and 6.7.3 however specify specific ebMS errors for these modules.
So the last part of the footnote, starting with unless is in conflict with the main text.