How to write a php client script to fetch data from the wsdl below

Question

http://zhx.17u.cn:9080/TBEWS/services/AirAvail/wsdl/AirAvail.wsdl

I have written one, but it doesn't seem to work:

$soap = new SoapClient('http://zhx.17u.cn:9080/TBEWS/services/AirAvail/wsdl/AirAvail.wsdl');

$parameters = array(
    'req' => array(
        'originDestinationInformation' => array(
            'departureDateTime' => time() + 36000,
            'destinationLocation' => 'SHA',
            'originLocation' => 'PEK'
        ),
        'pos' => array(
            'password' => 'cs', 
            'version' => null, 
            'officeCode' => 'S2'
        ),
        'travelPreferences' => array(
            'direct' => true, 
            'ETicketDesired' => true, 
            'vendorPref' => 'all',
        )
    )
);

$rs =  $soap->getAirAvail($parameters);

var_dump($rs); 

Any help would be appreciated.