Inherited permissions in Lion Server

Hope you can help

I'm trying to get to grips with ACLs and OS X lion server, I have a share which I need to allow full access to a group created in server app. I've configured the share and allowed the group full access including inherited permissions using an ACL so I would expect that once I have propogated permissions all folders within the share will have the same permissions applied including new files created.

However I still have POSIX and ACL's within the share permissions - Im assuming I understand POSIX permissions correctly in that they allow you to choose only read, read/write etc.. whereas full ACLS give you sub groups under the username/group with inheritance as an option as well as read/write etc... with tick boxes.

In terms of user experience, if I propogate the permissions then everyone has full access to the files/folders contained within but very quickly as they create new files - only the user that created them has access so the inherited permsissions no longer works. From other posts I have read POSIX permisisons does not support inherited so how does having ACLs and POSIX on a share effect this.

Just to add, the POSIX permissions on the share can not be deleted, the - sign is greyed out.

Any ideas where I'm going wrong here?

Thanks and Regards