Windows XP SP2 Internet Sharing over a Domain Network

I have a desktop (Workgroup) at home with 2 NICs. One has access to broadband (can’t change as MAC address is registered with ISP). Other NIC is connected to a D-Link Switch. My Client PC is also connected to the switch (My Client PC is configured in a Domain. Both machines run XP SP2 Pro. Internet connection sharing is enabled on the desktop via “Network setup wizard”. To complete the setup I need to run the wizard on my Client Desktop as well. But Client Desktop is registered with my office domain so the wizard will not run (says “Can’t run wizard as the computer is part of a domain”). How can I resolve this and enable internet access on Client Desktop by using the Internet connected desktop as a residential gateway?