ACLs not visible/respected by afp file sharing clients

I have a new Tiger server, and I am just using it as a file server and am running into a weird problem with ACLs not being respected (or even visible) by AFP clients.

I’ve set up ACLs on the server itself, and I have used the Effective Permissions Inspector to verify how access to a particular folder should look for “user x” — but when “user x” logs in (using regular old afp) from a client workstation, he is just seeing the regular posix permissions for folders and files.

In other words, ACLs are set up on the server, but clients are unable to see or use them – they are stuck with the posix permissions.

Does anyone have any idea what may be causing this?