Description:
------------
When I set a object property to unseted variable and than I call a SOAP function with this paramater, I get message
Fatal error: SOAP-ERROR: Encoding: object hasn't 'name' property .

Reproduce code:
---------------
class Passenger {
    var $name;
}


$wsdl =& new SoapClient(WSDL_LOCATION, array("trace" => 1, 'exceptions' => 0));
$p = new Passenger;
/* if ($xyz === null) $xyz = null; //if here is this row, it's works fine otherwise calling SOAP function failed */
$p->name = $xyz;    //$xyz is not set!!!
$wsdl->setPassenger($p);   //call SOAP function failed