NT 4.0 to 2003 Upgrade

We’ve been trying to resolve an issue but have had several different answers.

We have an environment with 3 NT 4.0 Servers with a PDC and BDC.

We have a brand new Server with Windows 2003 installed. Our plan is to add the Windows2003 Server to the Domain as a BDC and then promote it to the PDC after the users are replicated on this new Server.

We will NOT be using the Active Directory initially and plan on using a “mixed” environment.

Can anybody tell me definitively if this will be a problem?

Step 1) Add W2003 server to NT 4.0 Domain as BDC (not using Active Directory)
Step 2) Promote new W2003 Server (Step 1) as the PDC

Any help is greatly appreciated ASAP!!