Brett

All i can say is that it was there for me (N900 from Nokia UK) in the list, i just didnt look carefully. what i found was that although list of service providers was alphabetical - Nokia Messaging was 2nd on list under Mail for Exchange so check the list and look at the top.

Email - then click on Email drop down menu - New Account - aacount set up welcome opens - Next - account setup account details - Service Providers - Nokia Messaging

hope that helps