NFS and global user names

I'd like to map user names on different hosts to the same ID when they're communicating using NFS. There's a program, ugidd.rpc, that handles that. The problem is that ugidd.rpc appears to be incompatible with the kernel-based version of NFS. Has anyone found a way to do what ugidd.rpc does with a kernel-based NFS server? Paul Abrahams