csso.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">

    <parameters>
        <parameter key="assetic.filter.csso.bin">/usr/bin/csso</parameter>
        <parameter key="assetic.filter.csso.comments">null</parameter>
        <parameter key="assetic.filter.csso.force_media_merge">null</parameter>
        <parameter key="assetic.filter.csso.restructure_off">null</parameter>
        <parameter key="assetic.filter.csso.usage">null</parameter>
    </parameters>

    <services>
        <service id="assetic.filter.csso" class="Gremo\AsseticExtra\Filter\CssoFilter">
            <tag name="assetic.filter" alias="csso" />
            <argument>%assetic.filter.csso.bin%</argument>
            <call method="setComments">
                <argument>%assetic.filter.csso.comments%</argument>
            </call>
            <call method="setForceMediaMerge">
                <argument>%assetic.filter.csso.force_media_merge%</argument>
            </call>
            <call method="setRestructureOff">
                <argument>%assetic.filter.csso.restructure_off%</argument>
            </call>
            <call method="setUsage">
                <argument>%assetic.filter.csso.usage%</argument>
            </call>
        </service>
    </services>
</container>