i have a 05 silverado ext. cab that came with a tonneau cover. i recently purchased a tool box so i can haul around all of my tools for work. i want to customize the tonneau cover so it fits with the tool box on. i know it can be done. i started taking apart my tonnea cover which is a access brand. my questions are, how would one go about customizing it. i would prefer to cut the tonneau material towards the tail gate. because one of the support bar's straps that hold it in place ripped. any help would be appreciated!