[html] CSS vertically align floating divs

I have a div (#wrapper) containing 2 divs standing side by side.

I would like the right-div to be vertically aligned. I tried vertical-align:middle on my main wrapper but it is not working. It is driving me crazy!

Hope someone can help.

http://cssdesk.com/LWFhW

HTML:

<div id="wrapper">
  <div id="left-div">
    <ul>
      <li>One</li>
      <li>Two</li>
    </ul>
  </div>  
  <div id="right-div">
    Here some text...
  </div>
</div>

CSS:

#wrapper{
  width:400px;
  float:left;
  height:auto;
  border:1px solid purple;}

#left-div{
  width:40px;
  border:1px solid blue;
  float:left;}

#right-div{
  width:350px;
  border:1px solid red;
  float:left;}

ul{
  list-style-type: none;
  padding:0;
  margin:0;}

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