cakephp webservice

I have problem in creating web-service using cakephp .
this what i do to create this web-service .
I use NuSOAP - Web Services Toolkit for PHP for this.
I create a controller called WsController and import the library on it.

class WsController extends AppController{

var $uses = array();

function info()  {
    $this->layout= null;
	$server = new soap_server(); 


    array('x' => 'xsd:integer','y' => 'xsd:integer'),        
    array('z' => 'xsd:integer'),   
    'documentation'     // documentation 


 function sum($x,$y){ 
	return new soapval('return','xsd:integer',$z);


and i create the clint in controller action like this

function index() {
   $wsdl = 'http://localhost/asd/ws/info?wsdl';
   $client = new nusoap_client ( $wsdl, true );

   $this->client = new nusoap_client($wsdl, true);
   $param1 = array ('x' => 2, 'y' => 1 );
   $a = $client->call ( 'sum', $param1 );
    echo $a;

it don't do any thins although that i create this in non cake project and its work very well

hope some one tell me what is the best practise to create web-service in cake php