CWZXT0106W SOAP 1.2 extensibility elements are not supported.

Explanation
SOAP 1.1 extensibility elements are supported.
User response
To edit the WSDL file so that it uses SOAP 1.1 instead of SOAP 1.2, change the namespace from http://schemas.xmlsoap.org/wsdl/soap12/ to http://schemas.xmlsoap.org/wsdl/soap/.