php - How to create Date format in Nusoap server side? -

i make simple web service using nusoap & php server. in server page want instanciate date object , return client. part of complextype (struct). read solutions soapval() function can not make work. how can return date?

//complexlogintype $server->wsdl->addcomplextype('userinfo','complextype','struct','all','',     array(      'id' => array('name' => 'id','type' => 'xsd:int'),     'lastname' => array('name' => 'lastname','type' => 'xsd:string'),     'firstname' => array('name' => 'firstname','type' => 'xsd:string'),     'address' => array('name' => 'address','type' => 'xsd:string'),     'position' => array('name' => 'position','type' => 'xsd:string'),     'manager' => array('name' => 'manager','type' => 'xsd:int'),     'password' => array('name' => 'password','type' => 'xsd:string'),     'date' => array('name' => 'date','type' => 'xsd:string')) ); 

my usage of soapval();

$date = new soapval('token', 'datetime', '2006-12-19t19:51:12.174z'); 

in service nusoap code working

$server->wsdl->addcomplextype(      'order_type',     'complextype',     'array',     'sequence',     '',     array(         ...         'date_trips' => array('name' => 'date_trips', 'type' => 'xsd:date'),         ...     ) ); 

and service takes date in yyyy-mm-dd format.