Do <import> and <include> support extensibility elements?

I'd like to clarify which WSDL elements support extensibility elements.

Part 1, section 6.1 Element based Extensibility states:
WSDL 2.0 allows namespace-qualified *element information item*s whose
[namespace name] is NOT "http://www.w3.org/@@@@/@@/wsdl" to appear among the
[children] of specific *element information item*s whose [namespace name] is
"http://www.w3.org/@@@@/@@/wsdl".

The word 'specific' suggests some WSDL elements do not support extensibility
elements. This is backed up by the WSDL 2.0 schema at
http://www.w3.org/2005/08/wsdl/wsdl20.xsd which indicates that all
WSDL 2.0elements except <import> and <include> support extensibility
elements.

However, in Part 1 all of the sections that describe the xml representation
for each WSDL element state that the [children] of the WSDL element may
contain:
Zero or more namespace-qualified *element information item*s whose
[namespace name] is NOT "http://www.w3.org/@@@@/@@/wsdl"

i.e. this text applies to <include> and <import> too, in sections 4.1 and
4.2, which seems to contradict the schema.

Is this correct? Can <include> and <import> have extensibility elements?

Thanks,
John Kaputin.