[O] publishuing in html5

[Catonano]

I' m trying to follow the examples at this page

http://orgmode.org/manual/HTML-doctypes.html#HTML-doctypes

to transform

     #+BEGIN_ASIDE
     Lorem ipsum
     #+END_ASIDE


in


     <aside>
       <p>Lorem ipsum</p>
     </aside>

but it doesn't work, I still get

<div class="aside">
<p>
Lorem ipsum
</p>

</div>

I tried to both include the directive in the "group" in the project
definition AND using

#+HTML_HTML5_FANCY: t

in level-0.org

What am I missing ?