the same thing has happened to me since ea released the liveeditobjects cheat. the only thing that ever works for me is starting a build without the mods enabled,placing the debug items and then enabling the mods and logging out then logging back in to retrieve cc. i hope someone finds a solution, because that's a very tedious way to build and i play primarily to build.
before anyone says i am not using the liveeditobjects cheat properly and that is why they don't appear, the cheat works just fine and dandy with the mods disabled and stops working with the mods enabled. i have played like that for a long long time.