Some important questions here:
Version of Notes - Exch (and am presuming Win NT4).
It sounds like you are dealing with Exchange 5.*, Windows NT 4 and Notes {doesn't matter}, Since active directory would allow you to create the Windows Domain accounts, including exchange MB and then the Domino Synch tool would import those users.
Is that correct?
1. Are you trying to REGISTER the Notes Users so that they have ID's, Mail DB's, Group membership, etc OR
2. Are you simply creating PERSON DOCUMENTS so that the users can access the domino server without using a notes client (ie authenticating using names and passwords via http, pop3, imap, ldap, nntp, smtp, etc)?
The difference between 1 and 2 is HUGE!!
Why not create the NT/Exchange users and then use the Domino synch tool (NT Domain OR AD) via the administration client to create the users into your Domino Directory.
That would take about 11 clicks, verses hours of coding...
Hope this helps.
Mat.