The service is this

        <service id="routing.loader.php" class="%routing.loader.php.class%" public="false">
            <tag name="routing.loader" />
            <argument type="service" id="file_locator" />
        </service>

So you could create a subclass of `Symfony\Component\Routing\Loader\PhpFileLoader` and make the service def like this:

    <parameter key="routing.loader.php.class">Zikula\Bundle\CoreBundle\Routing\\Loader\PhpFileLoader</parameter>

        <service id="routing.loader.php" class="%routing.loader.php.class%" public="false">
            <tag name="routing.loader" />
            <argument type="service" id="file_locator" />
            <argument type="service" id="service_container" />       
        </service>