Problems migrating GroupWise6.5 to OL2k3

Hi we are migrating our GW 6.5 system to Exchange 2003. When we attempt to migrate a mailbox using the proper procedures of setting the proxy to give all access to the migrating user, it produces an error at the end about not having the proper security and only migrates the mail. Contacts and the calendar are not migrated. We are using the utility that microsoft supplies with Exchange 2003 to migrate forign email systems but it’s only options go up to GW 5.5. I am wondering if that is the cause of my problems and if it is I need to know what program will successfully migrate mailboxes to exchange including the address book and calendar.
Thanks
Pete