The feature you want is a flange, but as far as unfolding, stampings do not carry the right information to do accurate unfolding. This is the same as not accounting for thinning with die forms. these are all approximations. Only true sheetmetal bends can be managed with the appropriate K-factor (stretch and crush).
I agree with Dan on this one that sheetmetal really is not going to provide any significant advantage with this task.