New style property created, but doesn't appear in CSS

[cclaerhout]

I've created a a new style property in Appearance=>Styles=>Master Style=>Style Property Groups (in the Master Template), but when i'm looking into CSS, I can't find the class. Do I have to create a special CSS template too ? Isn't it automatically created ?

 

[cclaerhout]

I've just read the CSS Templates Help, so it seems the Style property pages are a kind of interface to change on the fly the CSS templates. So when I create an addon with new style properties, I must first add my customised CSS to the CSS template and only then, if I want, I can setup a page property to help user to customize the css code. Am I correct ?
If yes, can we add extra css to a specified CSS template using code event listeners ?