I have done that, but it seems that either these settings don't work on CentOS5.4, or I'm doing something wrong.
Is the remote machine also CentOS 5? NFS v4 is a relatively recent addition to Linux, so if your remote box is older, it might only be capable of NFS 3. I have to do that with our old CentOS 3 boxes here.
Yup, it's CentOS 5.4 :)
Are both machines in the same NFSv4 domain? You need to define the domain in the sysconfig/nfs file.
+1; the idmapdomains have to be the same and the users accessing the nfs share have to be "known" on the server either in its /etc/passwd or through nis-nisplus-ldap.
Also, an nfsv4 mount invocation is different from a previous nfs version's mount invocation.
If you are exporting /path/to/shareddir from nfsserver, you have to mount nfsserver:/ /path/to/mountpoint on your client
You may have to export with fsid=0 or fsid=root but it may be assumed if there isn't a directory exported at a higher level, but I have not tested it is assumed without.