This is not a simple update in pOwer store 4,
Power Store 4 uses an ajax function call to populate the results, so the Ajax code would need to be edited.
The post you are reading is probably for Power Store 3.
This sort of modification is beyond what we offer support for here in the public forum, we can help you implement this change through our premier support appointment:
http://www.webassist.com/premier_request.php