Update Mar 2012.
This procedure does not work with Lion or later but will work with Snow Leopard.
By default, folders/files created by Mac connected to StorNext SAN are read only by groups and guests.
Apply the following changes to make it 777, write/read for owner, group and guests.
This must be applied to each Mac client and a reboot required after making the new setting.
Follow this link for details: http://support.apple.com/kb/HT2202
Follow the steps in the section "Umask for user applications".
Set the umask to 000 in /etc/launchd-user.conf: "umask 000"
This will set the permissions of created folders/files to 777.
Excerpt from http://support.apple.com/kb/HT2202
Umask for user applications
In Mac OS X v10.5.3 and later, you can create the file /etc/launchd-user.conf with the contents "umask nnn". Do not include the quotation marks and replace nnn with the desired umask value, such as 027 or 002.
This will set the user's umask for all applications they launch, such as Finder, TextEdit, or Final Cut Pro, and control the permissions set on new files created by any of these applications.