[CentOS] nfs4 idmapd.conf user mapping

On my CentOS 6.3 machine, in /etc/idmapd.conf I've updated the
"[Mapping]" section of the config file:
Nobody-User = paulbsch
Nobody-Group = paulbsch

But the mapping is not working.  Files still show up as being owned by
"nobody".

On my Fedora 14 machine, with the exact same changes to
/etc/idmapd.conf, the mapping works perfectly and the files show up as
being owned by "paulbsch".

On the CentOS 6.3 machine:
nfs-utils-1.2.3-26.el6.x86_64
nfs-utils-lib-1.1.5-4.el6.x86_64

On the F14 machine:
nfs-utils-1.2.3-6.fc14.x86_64
nfs-utils-lib-1.1.5-3.fc14.x86_64

Would anybody have any idea why this is does not work on CentOS as it
does in F14?

Thanks...Paul...