I'm looking for a way to disable the link which has the text Item Name at the top of a product listing on the category page and sorts the products by ascending/decending order. I changed the + and - in the admin interface to be blank, but clicking on "Item Name" still allows the sort and there is no way to return to the order according to the customized order set in the product admin interface so I just want to disable the link totally. How can I do this - if not in the admin interface, where is it in the php code?