code: protected static function getMessagesAndVersionsFromImportedWsdl($import, $wsdlPath, $wsdlIdentifier)
      {
          $msgAndVer = [];
          $domXpath = null;
  
          $importPath = realpath(dirname($wsdlPath)).DIRECTORY_SEPARATOR.$import;
          $wsdlContent = file_get_contents($importPath);
  
          if ($wsdlContent !== false) {
              $domDoc = new \DOMDocument('1.0', 'UTF-8');
              $ok = $domDoc->loadXML($wsdlContent);
  
              if ($ok === true) {
                  $domXpath = new \DOMXPath($domDoc);
                  $domXpath->registerNamespace(
                      'wsdl',
                      'http://schemas.xmlsoap.org/wsdl/'
                  );
                  $domXpath->registerNamespace(
                      'soap',
                      'http://schemas.xmlsoap.org/wsdl/soap/'
                  );
              }
          } else {
              throw new InvalidWsdlFileException('WSDL '.$importPath.' import could not be loaded');
          }
  
          if ($domXpath instanceof \DOMXPath) {
              $nodeList = $domXpath->query(self::XPATH_ALL_OPERATIONS);
  
              $msgAndVer = array_merge(
                  $msgAndVer,
                  self::loopOperationsWithQuery(
                      $nodeList,
                      self::XPATH_ALT_VERSION_FOR_OPERATION,
                      $wsdlIdentifier,
                      $domXpath
                  )
              );
          }
  
          return $msgAndVer;
      }
docs: Get Messages & Versions from an imported WSDL file
  
  Imported wsdl's are a little different, they require a different query
  to extract the version nrs.
  
  @param string $import
  @param string $wsdlPath
  @param string $wsdlIdentifier
  @return array
  @throws InvalidWsdlFileException when the WSDL import could not be loaded.