3. Add to processor conformance section:
Mandatory extensions are those that
MUST be processed correctly by the
WSDL processor. If a mandatory extension element is processed, the WSDL
processor MUST either agree to fully abide by all the rules and
semantics signaled by the extension element's qualified name, or
immediate cease processing (fault). In particular, if the WSDL
processor does not recognize the qualified name of the extension
element, it MUST fault. If the WSDL processor recognizes the qualified
name, and determines that the extension in question is incompatible
with any other aspect of the document (including other required
extensions), it MUST fault.