I solved my problem editing the method cache in codeigniter/libraries/output.php.
function cache($time)
{
$CI =& get_instance();
$enable_cache = $CI->config->item('enable_cache');
$this->cache_expiration = (
(is_numeric($time) && $enable_cache) ?
$time :
0
);
}
I have no idea if this is the best place but at least it made some sence.
Tiago
