Dual network adapters

I have a client who has a desktop pc running win 2k pro. It has a network adapter configured for direct access to the head office server with a static ip address, I am not allowed to change any of those settings. I have installed a second adapter connected to an adsl router for internet access and VNC use. The pc has several remote desktop connections configured for head office services, however these do not work with the internet adapter enabled. everything else works fine. How can I configure the RDP connections to use the apapter I want it to use?