валидирую wsdl, например такой с помощью XmlValidatingReader, что-то вроде

XmlValidatingReader reader = null;
try {
    reader = new XmlValidatingReader(new XmlTextReader(fileName));
    reader.add_ValidationEventHandler(new ValidationEventHandler(handleValidationErrors));

    //здесь схемы:  "http://schemas.xmlsoap.org/wsdl/", "http://schemas.xmlsoap.org/wsdl/http/", "http://schemas.xmlsoap.org/wsdl/mime/",
    //"http://schemas.xmlsoap.org/wsdl/soap/", "http://schemas.xmlsoap.org/wsdl/soap12/", "http://schemas.xmlsoap.org/soap/encoding/"
    reader.get_Schemas().Add(schemas); 

    reader.set_ValidationType(ValidationType.Schema);
    while (reader.Read()) ;
}
...

и для http:operation выдаёт: The 'location' attribute has an invalid value according to its data type..

почему??
в http://schemas.xmlsoap.org/wsdl/http/ схеме английским по белому написано <attribute name="location" type="anyURI" use="required"/>