在XMLRPC中发送数组？

$message = new xmlrpcmsg(\'service.RegistrationDetails\',
    array(new xmlrpcval(
         array(\'EventId\' => new xmlrpxval($EventId, \"int\"), 
             \'ParticipantId\' => new xmlrpxval($usrId, \"int\")), \'array\') 
    )
);

$result = $server->send($message);

$message = new xmlrpcmsg(\'service.RegistrationDetails\',
    new xmlrpcval(
         array(\'EventId\' => new xmlrpxval($EventId, \"int\"), 
             \'ParticipantId\' => new xmlrpxval($usrId, \"int\")), \'array\') 
);