options_extension.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="knp_menu.extension.default_options" class="Knp\Bundle\MenuBundle\Extension\DefaultOptionsExtension">
            <tag name="knp_menu.factory_extension" />
            <argument>%knp_menu.default_menu_options%</argument>
        </service>
    </services>

</container>