AddThis

Facebook Send Button is not working

Here is my code, is the typical AddThis code, but with the difference that I have changed the like button to the like-send button. When I paste this in my site, it only displays the facebook like button and not the send button.

What am I doing wrong?

<!-- AddThis Button BEGIN -->
<div class="addthis_toolbox addthis_default_style ">
<a class="addthis_button_facebook_like" fb:like:send="true"></a>
<a class="addthis_button_tweet"></a>
<a class="addthis_button_google_plusone" g:plusone:size="medium"></a>
<a class="addthis_counter addthis_pill_style"></a>
</div>
<script type="text/javascript" src="http://s7.addthis.com/js/250/addthis_widget.js#pubid=ra-4e6f636f194223d3"></script>