Meta charset is moved down

I was having issues when trying to add a script tag just after the footer minified Javascript. I posted a question (http://wordpress.org/support/topic/how-to-load-script-after-embeded-before-minified-js?replies=1), but there are no answers yet.

Now I’m getting a validation error, because both styles and a script are rendered before the meta charset tag (which should be the first after head tag). This tag is just after the head tag, but this plugin seems to be re-writing after the head tag.

Any idea of how could I add this meta tag before the styles and scripts?

https://wordpress.org/plugins/w3-total-cache/