[Plugin: OptionTree] Textarea Simple reformatting CSS

I have a CSS Styling area using a TEXTAREA SIMPLE box but anytime I add CSS to it the code gets converted into HTML. Even if I use tags. The only solution I have found was to make it a TEXT line which is far from optimal.

I am using TINYMCE Ultimate

http://ww.wp.xz.cn/extend/plugins/option-tree/