In Notes Migrator 4.0, there is an alternate method to setting Notes forwarding. This can be done by turning a Notes person document into a foreign domain document.
There are three attributes that can be changed to turn a Notes person document into a foreign domain document. This is used to re-route mail for the notes user in question to exchange (through the connector) and to enable free/busy lookups to happen.
These settings can be used in lieu of setting forwarding on the original Notes person document (for mail routing) and syncing in a contact from Exchange (for free/busy lookup).
To use these settings you would put the following values in for each attribute:
Mail Domain: <name of foreign domain in Notes, usually Exchange>
Calendar Domain: <name of foreign domain in Notes, usually Exchange>