When a UNIX client attempts to use the mount command, they receive a Permission Denied error message?
If you used the wrong case, SFU 2.0 returns a NFS3ERR_ACCES which the client displays as Permission Denied.
If SFUSERVER has a Public share,
mount -F nfs SFUSERVER:/public /mnt
would generate the Permission Denied error message, but
mount -F nfs SFUSERVER:/Public /mnt
would not, as it used the proper case.