Problems with service plans overuse

[D@ve]

I have a problem with the oversue. There are some options where I want to allow overuse (especially traffic and disc space) and there are other options where don't (especially domains). How do I realize that without set the overuse options to "unlimit"? Can I block the domain ussage in generall some how? Like in confixx, where just the reseller could add new domains?

thanks and regards
Dave