RISHelp

Hi, we are currently relocating to a new site which needs about 600 brand new pcs to be imaged. unfortunatley we cannot move our PDC from the old site as there will be still users using the old site for a while. therefore my idea was to build a DC with DNS and DHCP on and move this to the new site so users can logon, get IP etc. this works correctly. my next idea was to build a ris server at the new site, this of which worked fine, but it cannot start the RIS service because it keeps saying the domain is unavailable even though it can see the new DC and AD at the new site. My question is how can i get RIS working without it being able to see the PDC. and does anybody have any advice on this? cheers, RIShelp