I'm designer, then I have not knowledge enough perhaps and it's difficult to me explain, I'm sorry.
I think I have this problem, I have not any alert
joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=10662
The patch doesn't solve the problem. Then, I use your component to change error page, but...there it's not any page to change. I wanted an alert page.
Anyway I solved the problem with a solution...not very good, but a solution... I have made a module with php to asign to articles registered
<?php $user =& JFactory::getUser();
if ($user->guest) {
echo "</br>Atención. Solo los usuarios registrados pueden ver este contenido. </br>Para más información puede consultar blabla";
} else {
echo "</br>Hola {$user->name}. Está usted visitando contenido restringido ";
}?>
This is Ok. But it's a pitty it is not automatic when article is for registered. But... OK, this is not a problem with your component .
¡Saludos!¡Gracias!