Centering right .span9 content in Twitter Bootstrap?
===

My Bootstrap setup is very simple and quite similar to this [example][1]. I've a **sidebar of the left and a content on the right**. The simple task i'm tring to accomplish is centering the right side of the page.

More in general i'd like to center any div placed inside `div.span9`. I've used `.span4 .offset4` but it doesn't work:

    <!--End of sidebar -->
    <!-- Right side -->
    <div class="span9">
    	<!-- Right side-->
    	<div class="form-container span4 offset4">
    	    <form class="form-horizontal">
                <!-- ... -->
            </form>
    	</div>
    </div>
    <!--/span-->

Here you can **see the complete code** and a [live example on jsFiddle][2]. Any help would be much appreciated, thanks.


  [1]: http://twitter.github.com/bootstrap/examples/fluid.html
  [2]: http://jsfiddle.net/8PdQc/2/