How do you include a plugin in Compass (through Assetic) for Symfony2?

I have installed the compass-rgbapng plugin, but am struggling to to include the plugin for use in Symfony2.

I need to add the require "rgbapng" to the compass config file, but I am unsure how to do this through Symfony2.

Does anyone know how I can do this?

Solution

I think something like that in app/config/config.yml should helps:

# Assetic Configuration
assetic:
    filters:
        compass:
            plugins:
                - rgbapng