We present a trader design that is focussed on integrating already existing components. This design has been used for implementing or enhancing traders on CORBA and ANSA ware platforms. For CORBA we show, how this design can be used with special focus on type management. Interworking between autonomous distributed platforms requires a contract to be established. Therefore we have developed a new negotiation protocol based on policies, contracts and trader links. Besides establishing federation contracts, gateway objects have to be introduced to enable interworking distributed platforms. Server proxies, group proxies and interceptors are possible ways to realize gateway objects.