add itemid to search results page

[kobiavr]

hey
how can i add itemid to search results page ?
the url look like this:
http://www.test.com/index.php?keyword=test&limitstart=0&option=com_virtuemart&view=category
and i want it to be like this:
http://www.test.com/index.php?keyword=test&limitstart=0&option=com_virtuemart&view=category&Itemid=117
i try with this file but i'm not so good in php
/modules/mod_virtuemart_search/tmpl/default.php

Does anyone have an idea?

thank you
kobi