[Plugin: Custom CSS for Posts and Pages (CCSS)] Not changing CSS

I don’t get what I’m missing. I have made a folder, and .css files. And inside edit post I can choose between six .css files, but no matter what I put inside the css files, nothing changes in the posts.

Any known bugs or compatibility issues?

edit: I can see that the css is loading, but is overided by style.css. How can I make it load before/after?

edit: The theme loaded css files after wp_head(). When replaced it now works.

http://wordpress.org/extend/plugins/custom-css-stylesheet-for-posts-or-pages/