By default you shouldn't have to change anything in the templates. The only thing you should have to edit is in the admincp options. What version of vb do you have? If you are using the legacy version and you have follow the instructions and you are showing the searchresults.php page correctly (without results) when you go to
http://www.. ..com/searchresults.php but it is not showing up at all in the drop-down then there is a very good chance that another hack is interfering with this one. This is possible.
I will be back on Monday.