If Assetic is used to compile JS and CSS files then one of two things must happen:
1. Compiled file can be served via something like old style.php
2. Assetic can store compiled files in specific directory, then files will be served without PHP.
If stylesheet is served with something like old style.php, URLs in CSS files will have to be rewritten. Each image it links to will have to be located using styles tree and its URL changed. For example,
url('./images/foo.png')
will have to be changed to url('styles/progreen/images/foo.png')
If stylesheet is stored in specific directory, there are two possibilities:
1. Rewrite URLs like in example above.
2. Replicate whole style directory in that temporary directory.
Examples in previous post assume that whole directory is replicated. I'm fine with ether way, but I think replicating whole directory is much cleaner.