eztc.php doesn't compile siteaccess in extension

eZSystem recommends to put custom siteaccess in a dedicated extension but in such case eztc.php doesn't compile templates of these siteaccess.

Steps to reproduce

create a new extension with a siteaccess and some templates
activate it in override/site.ini.append.php
run php bin/php/eztc.php -s yoursiteaccess