Hi, I am installing a tub surround and have a window to go around. I am wondering how to install the casings around it. I have a PVC window and the jambs have been cut flush to the surround. I bought plastic casings to try and minimize moisture damage but have no clue what adhesive to use to adhere them to the wall. I was assuming silicon but that doesn't stick to the shiny surround very well. Do I use tub surround adhesive or contact cement? Any help would be appreciated.