Matlab computations done over Apple Filing Protocol (AFP) depend on POSIX permissions, ignores ACLs

I'm a system administrator and have never used Matlab, so forgive my general ignorance of the program.

My users have encountered problems when executing scripted Matlab actions over AFP to a Mac OS X Server 10.6.7 where the access control list (ACL) should allow actions, but the POSIX-style permissions disallow the activity.

It seems as if Matlab, run locally on the Mac workstations on datasets on the remote server, ignores the ACLs entirely. This is the only application I've ever seen behave this way. The server's filesystem is HFS+J and all other activity is performing as expected. These users cannot use CIFS because of our integration with external directory systems.

In this example, the directory bxdata, the members of the group cibturner should be able to modify the files. Indeed, they can using any other method except via Matlab scripts. When the Matlab script hits these files, the POSIX permissions of 644 disallow modification. It's as if the ACLs are irrelevant.

[root@cib 16:00:24 /14181.2_5sM]# ls -leh@ bxdata/
total 128
-rw-r--r--+ 1 kel32  staff    18K Feb 15 09:31 TS-5sMath030708-21073-1.edat  
 0: group:cibturner inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown
 1: group:cibsrlocaladmins inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown
 2: group:crcservergroup inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown
-rw-r--r--+ 1 kel32  staff    25K Feb 15 09:31 TS-5sMath030708-21073-1.txt
 0: group:cibturner inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown
 1: group:cibsrlocaladmins inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown
 2: group:crcservergroup inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown

Because this server has HIPAA data, security is critical. We are not using networked home directories or SAN technology. The MatLab program is run on the user's hard drive; access is granted via Kerberized AFP.