The IDL exception refusal maps onto the Dylan class BankingDemo/account/<refusal>. Its member, string reason;, maps onto a slot BankingDemo/account/refusal/reason :: CORBA/<string>.
Note that BankingDemo/account/<refusal> is a subclass of CORBA/<user-exception> and, by inheritance, of Dylan <condition>. This means that CORBA user exceptions can be raised on the server, and handled in the client, using the standard Dylan condition mechanism.