Trouble remotely joining a 2003 domain

I have 6 Windows 2000 PCs in a domain on a Windows 2003 Server. Everything is working fine in the office. But I’m having trouble with remote dial in. I have given the remote PC and user accounts on the 2003 server with dial in permission. I have given the user various permissions, including Administrator. When I dial in, the 2003 server authenticates me, but I am only a member of a workgroup called Workgroup, not the domain. As a result, I cannot see the server in My Network Places and I cannot ping anyone on the office network. Any ideas?