client.setHelo("relay.localdomain");
BackendServer backendServer = new BackendServer();
backendServer.setHost("localhost");
backendServer.setPort(8026);
backendServer.setClientFactory(client);
RelayDestination relayDestination = new RelayDestination();
relayDestination.setBackendServer(backendServer);
RecipientSpecificationDestinationPair recipientDestinationMapper =
new RecipientSpecificationDestinationPair();
recipientDestinationMapper
.addRecipientSpecification(new RecipientSpecificationFactory()