Correct me if I'm wrong but, domains, actions and are not part of the standard "objects" that bindings support, nor are they native to Z-Wave. Z-Wave uses the configuration command class, that's more or less the interface. I'm not sure how the rest of the administration of Items is done from HABmin, but I think you use domain and actions to structure your configuration data and operations like that.

But it could be that I'm overlooking something. I must admit that I still have to install HABmin. I will do that tonight.