Originally posted by janis
Obviously, I can't use 'add reference' in pres. layer, because I don't know where business object will be (on which server).
The business layer and GUI layer should always be independant, and should never interact directly. You should have a Controller class sitting between the two that handles all the communication.

As for remoting, can't help you there I'm afraid. Have a look at the Factory Design Patten as this would enable you to implement code that react to runtime situations.