Migrating nt4 to 2k3 and SIDs

[Caustic]

I'm in the process of migrating my accounts between an NT4 domain and a 2k3 AD. I have a trust set up and I've turned off SID filtering. How do SID histories work with my user accounts. When I migrate user accounts and groups to the 2003 AD should they still have access to all the resources on the NT4 domain?

What I'm trying to prevent is having to readd all the newly created AD groups to resources in the NT4 domain.

Can anyone push me in the right direction for how I can accomplish this with SID histories or what I'm missing? After I moved the user accounts with SID history I'm not able to access the old NT4 resources. Also, migrated accounts are not able to access their Exchange mailboxes as I would understand they are able to with migrated SIDs.

Thanks.