samba - Apr 2011 - Simple question about Samba3 and Samba4 in the same site

I want to deploy a test server with the same SID and same users as the 
samba3 server.
My idea is next:
- Samba3 PDC running actually is located throught WINS
- Samba4 is located by DNS putting his own DNS server in the client 
configuration.

The two servers are in the same network/VLAN separate from the users 
network/VLAN.

This test could give me any problem?

Thanks.

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Alejandro Escanero Blanco
Servicio de Inform?tica Sistemas - GISI
Tel:  671 569 262 (769262)
Edificio Empresarial Aljarafe, mod. 36
41940 Tomares (Sevilla)