Yes, I've already stopped and restarted the NFS service on Windows, and on Solaris boxes "/etc/rmtab" is empty, even on etest where the filesystem is mounted.

About Samba, as far as I know there is no Samba Client fo SunOS, except Sharity or Sharity Light which I've played with some time ago, with a little success..... However, since eprod is a production system, I can't and I don't want to install anything on it, also because I don't need a persistent shared directory: it's only for temporary staging a big amount of data, after that I will umount the shared filesystem from both Solaris boxes.