Converting from M$ Exchange to SuSE email

Hi all, Does anyone know where to find specific information required to convert my mail server from M$ Exchange to SuSE Email Server II? I've got the server installed and running, but not configured. Under the Postfix section, it requires a 'Name of Relay host'. I presume the same information must be in Exchange somewhere, but I can't find it. There are numerous other parameters that I presume must be set up for this to work. Any help is very welcome. Thanks, Mark