Create an instance of the type which was declared to be used to
represent extensibility elements with qnames matching elementType,
when intended to exist as children of the specified parentType.
Creates the extension registry, and sets the defaultSerializer
and defaultDeserializer properties to instances of an
UnknownExtensionSerializer, and an UnknownExtensionDeserializer,
respectively.
Returns an InputSource pointed at an imported wsdl document whose
parent document was located at parentLocation and whose
relative location to the parent document is specified by
relativeLocation.