1. install new w2k box as member or dc promo to w2k AD box.
2. install ADC. You do not need to configure Connection Agreements at that point.
3. put in e2k CD, do setup\i386 setup /forestprep. You will be asked whether you want to create new Organization or Join Existing. You want to Join Existing. The account you are running /forestprep w/ must be in Enterprise Admins, Domain Admins, Schema Admins. The account must have Service Account Admin permissions at 3 levels in Exch 5.5 Administrator, Org, Site, and Configuration container, on Permissions Tab at those locations in Exch 5.5 Admin.
4. if e2k box is w2k DC, you must change LDAP port on Exch 5.5 box to something other than 389 (default for w2k ldap), to like 390.
5. if somethings not right you will run into problems there, during /forestprep. If there is authentication problem to Exch 5.5 Directory during /forestprep, make sure:
a. Service that Logs On Active Directory Connector Service is same as what you are running /forestprep w/ and that it is not in UPN format (email@example.com) but in user\domain format
b. NTLM Authentication is enabled on LDAP on Exch 5.5 box.
6. if setup /forestprep finishes, then run setup /domainprep. After /domainprep go back to cmd promtp and just run Setup and chose Typical install.
7. IIS must be on E2k box, and NNTP must be subcomponent of IIS, and w2k box must be at least at SP1, SP2 preferred.
8. Create Connection Agreements, move mailboxes from Exch 5.5 to e2k. Create Public Folder Connection Aggreement.
9. Before install E2k must point to w2k DNS box only and DNS must be working correctly.