<?php 
require_once 'SOAP/Client.php';
$client = new SOAP_Client('http://localhost/rot13.php');

// this namespace is the same as declared earlier
$options = array('namespace' => 'urn:SOAP_Server_rot13');

$rotated_string = $client->call("rotate",
                                $params = array("input" =>
                                                "Rotate Me!"),
                                $options);
print $rotated_string;
?>

Ebgngr Zr!