It should be added to the javascript where your menu is created immediately below the menu html on the included page at the very bottom.
<script type="text/javascript">if(window.attachEvent) { window.attachEvent("onload", function() { cssmw.intializeMenu('cssmw',{select_current: 1, orientation: 1}); }); } else if(window.addEventListener) { window.addEventListener("load", function() { cssmw.intializeMenu('cssmw',{select_current: 1, orientation: 1}); }, true); }</script>
The select_current argument will be set to 0 for a menu that doesn't highlight the current page.