Customer has a DMC080 and the DMC has 5 features that are programmed in the phones. You can add, delete and move these 5 features through DMC Feature List in System programming. However, you can only use those 5 features. For example, one of the features is Park. I want to delete it and put Voice Mail Transfer in its place. Nortel says you can't change those 5 features. Has anyone experienced this? If so, why can't you change them?