如何从wsdl页面获取详细信息

我一直在使用http://www.mobilefish.com/services/web_service/countries.php?wsdl文件获取国家地理信息。但我一直未能通过肥皂来实现它。请在这方面给我一些建议

<?php
require_once('ws/lib/nusoap.php'); //including the file 
$client = new nusoap_client('http://www.mobilefish.com/services/web_service/countries.php?wsdl');
$geo = $client->call('countryInfoByIana',  //calling the method of server object and 
              array('ianacode' => 'us'));
              var_dump($geo);
?>

帮助指南是http://www.mobilefish.com/tutorials/web_service/web_service_quickguide_countries.html页面。请帮帮我。