There shouldn't be anything special. The NFS mount process is pretty straight forward, and doesn't have much to do with the VMware side of things (aside from needing it). This seems to be a pretty comprehensive thread for troubleshooting something similar:
http://www.networkedmediatank.com/showthread.php?tid=7882
I think RHEL 6 introduced NFS v4. However, when you run mount ... it should easily auto detect the NFS mount on the far side.
mount ourip:/vcd_transfer /opt/vmware/vcloud-director/data/transfer
Make sure that ourip:/vcd_transfer allows for root to mount it, and that the vcloud user/group can read and write to it.