we can’t support 3rd party plugins since this would go beyond the scope of things we can do. We are only a small team and we can’t provide support for all plugins out there sorry! W3C Total Cache should work fine with our theme so maybe get in touch with them and ask them about it.
Thanks guys, these directions solved my problems!
I’ve also activated Set expires header in the subsections General, HTML & XML, Media & other files of the section Browser Cache. I left the other options as default. This works great.