pear soap pass paramter
$param = array(
'user_id' => new SOAP_Value( 'user_id', 'int', 1),
'fields' => new SOAP_Value( 'fields', 'array', array('username','city') ),
);
echo ( $client->getUserInfo($param).'<br />' );
ref: http://www.bangbangma.com/forum-4-1.html
