This is similar to an issue that dirkvdo had, but different. We have an Exchange 2007 server and a Domino 7.02 server in the same domain. Email sent between the two works just fine. However, when a Notes user sends a message to an Exchange user with other Notes users addresses in any field, then all the addressed users get the message correctly. When the Exchange user Replies to all, then the messages for the other Notes users bounce. The addresses of the Notes users appear in the Exhange reply as <username>/<domino domain>@<sharednamespace> which is how they show up in the eMail Address column of the People view in the Domino Directory. As noted we use SMTP for routing not the connector. The connector is just used to populate directories.