Bug#481421: nfs-common: mounting nfs4 file system fails with 64-bits kernel

Package: nfs-common
Version: 1:1.1.2-4

The Debian s390 port has a 32-bit userland, but has both a
32-bit (-s390) 
and a 64-bit (-s390x) kernel.

If I try to mount an nfs4 file system using the 32-bit
kernel all is OK, but 
when I do the same with the 64-bit kernel it fails as
follows:

# mount  -t nfs4 elrond.fjphome.nl:/project /srv/project
mount.nfs4: an incorrect mount option was specified

An strace is attached for both kernels.

System is the Hercules S/390 emulator running Debian
unstable; Debian kernel 
2.6.24-6 (upstream 2.6.24.4).

Cheers,
FJP