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Notes on backup and restoring ACLs using dump file - http://projectenvision/blog/4/Enable-Support-for-ACL-in-Debian-Ubuntu
Good article on masks but I think it might be wrong - http://novell/documentation/suse91/suselinux-adminguide/html/apbs03.html
Looks like another good read on masks in ACLS - http://users.suse.com/~agruen/acl/linux-acls/online/