Thanks for coming to the forums. You will need to uninstall the trial version completely from the console. If you do have a disk for the game make sure to eject it before you uninstall. To be safe would uninstall game and trial. Once they are done power cycle the console. When the console comes back on, go to settings>network>network settings> and go offline, insert your disk game and install the game. This will install the game offline so no chance of installing the trial. Once installed go back online and update game.
Hope this helps.
Brad"
This isn't working for me i tried it this morning, but it can help one of you maybe? 🙂