require_once("lib/nusoap.php");
    $private_key=file_get_contents('client.pem');
    $private=der2pem($private_key);
    $local_cert = (string)$private;
    $ws = 'url/wsdl';  //wsdl file
    //define the soap server location
    $vLocation = "xxxx";
    $client = new SoapClient($ws, array(
    "location" => $vLocation,
    "trace"=>1,
    "exceptions"=>1,
    "local_cert" => $local_cert
    ));
    $username = 'username';
    $password = 'password';
    $headerbody = array('username ' => $username,
    'password ' => $password);
    $ns = 'xxxx'; //Namespace of the web service.
    $header = new SOAPHeader($ns,'requestHeader', $headerbody,true);
    $client->__setSoapHeaders($header);
    $params=array('name'=>'monocept');
    try{
    print_r($client);
    $op=$client->authHelloWS($params);
    }
    catch (SoapFault $fault) {
    trigger_error("SOAP Fault: (faultcode: {$fault->faultcode}, faultstring: {$fault->faultstring})", E_USER_ERROR);
    }
    function der2pem($der_data, $type='CERTIFICATE') {
    $pem = chunk_split(base64_encode($der_data), 64, "n");
    $pem = $type.$pem.$type;
    return $pem;
    }