Wow 10 years have passed and I'm a bout to try one, not the oner in the original post. Any ideas will be greatly appreciated.

Try to find a b2evo plugin that is close to what you want, then try mixing the plugins ;)

Thanks

I've got the basics and made a simple one that just adds an html line in the head section. It's a start :) Totally useless apart from learning the basic format/syntax.

As I learnt through #10, #11, #12 of http://forums.b2evolution.net/request-plugin-for-mathematical-expressions