title: jquery.animate background-position doesn't work
body: <p>I'm trying to create a background position change with animation. <br>
  but for some reason it's not working.</p>
  
  <pre><code>&lt;script language="javascript" src="http://code.jquery.com/jquery-1.5.min.js"&gt;&lt;/script&gt;
  &lt;div class="moveme" style="height:80px;width:240px;background-image:url('http://www.google.de/intl/en_com/images/srpr/logo1w.png');background-repeat:no-repeat"&gt;&lt;/div&gt;
  
  &lt;script language="javascript"&gt;
      $('.moveme').css("background-position","0px 0px").animate({backgroundPosition:"-100px 10px"});
  &lt;/script&gt;
  </code></pre>
  
  <p>ideas?</p>