Sony Ericsson Z520 / Z525

Does anyone have any input on being able to unlock Cingular Protection on Themes and Ringtones? These phones are coming with themes, ringtones, etc. that can be downloaded from Sony Ericsson, but they are file protected so that they cannot be deleted. Therefore, you do not have room to add the ones you would prefer to have. Personally, I do not appreciate having to keep the ones that I don't care for that are taking up memory space. PLEASE HELP!!!