i was working on that too. The best i can get it to do is to show that the map is damaged. (Not signed). I was using maps from the one player mode too like the Penthouse. Try putting them in your E:\TDATA folder. In there you will find where xbox live stores all the downloaded maps. if you have any success, let us know. Otherwise you will need it to be signed, and no one here will answer you about signing files