I found the function.
I paste here the code so if someone wants to use it elsewhere he can do. I see it as a way to expand protector to other parts of your website.
I found that the class is loaded, with echoing the php function "get_declared_classes". So I started the work.
First call protector class that is loaded inside xoops. Than you can call a function of that class.
Here is an example of calling the class and the log and deny by htaccess function.
$protector = new protector;
$protector->output_log("IPB Register Exploit"); $protector->deny_by_htaccess();