style a li if the link in it is active

Hello,

I have a small problem while developing my theme.
I have an active link within a drupal menu:

<ul class="menu"><li class="first leaf"><a title="" href="/3mw/nieuws">#nieuws</a></li>
   <li class="leaf"><a title="" href="/3mw/onswerk">#onswerk</a></li>
   <li class="last leaf"><a class="active" title="" href="/3mw/versvandepers">#versvandepers</a></li>
</ul>

Now I want to style the LI with the child .active but I cant find a way to do this.
So I was wondering if there is a way to add the class active to the li class if the child li is active.
Is there any way to achieve this? Or is there another workaround?

I am outputting the menus as blocks.