Thanks all for your responses to my query about how to backup a NetApp with Legato Networker server on UNIX. The answer seems to be that such cannot be accomplished without losing the NT ACLs.
I also received unofficial indications that the seemingly fabled Networker client for NetApp will be available in May. I presume that people who buy that product at that time will also become de facto beta testers, since nobody came forward to say they're running it now.
I'm planning to roll out the new server in May. I can't specify hardware that I don't know for certain I can back up on May 1. Oh well....
Greg