To add an additional search engine, you need to use the following code:
pageTracker._addOrganic("name_of_searchengine","q_var");
The “name_of_searchengine” should be replaced by the name of the search engine you want to track. The “q_var” should be replaced by the specific query you want to track.
Your code should look something like this from Google Analytics Support:
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
var pageTracker = _gat._getTracker("UA-xxxxxx-x");
pageTracker._addOrganic("name_of_searchengine","qvar");
pageTracker._trackPageview();
</script>
Remember the UA-xxxxxx-x code will need to be replaced by your specific Google Analytics account number.