Output minimized css using compass, assetic and Symfony2

I'm trying to let assetic dump some compressed asset files which are filtered by compass. In my config.rb I have:

output_style = :compressed

And, as I'm using Symfony 2.3, here's my config.yml for assetic:

assetic:
    debug:          %kernel.debug%    
    filters:
        cssrewrite: ~
        sass:
            bin: /usr/local/bin/sass
        compass:
            bin: /usr/local/bin/compass
            load_paths:
              - "/var/lib/gems/1.9.1/gems/zurb-foundation-4.3.1/scss/"

As you can see I'm also explicitly adding the foundation gem, because compass couldn't find it (more problerms with my setup?).

The thing is, it spits out compressed css if I compile by hand, so

compass compile --force

works like a charm, but

php app/console assetic:dump --env=prod --no-debug --force

doesn't.

So clearly I'm missing an assetic config, but I'm clueless as to which one. So my quesion is, is assetic supposed to handle this automatically, or is there a setting of config I missed?

Any help is greatly appreciated!

Solution

Well, I just used the yui_css compressor to deal with the compression. Seems more logical that way, as assetic is first combining all files generated by compass and only then compresses it (in my case now with yui_css).

So to answer my own question, it's not really a setting in assetic, I misunderstood the process by which filters are applied I think.