Issue with ACL/deleting files

Hi!

I have a foder named Pictures set with the following ACL:
The group Publishers is allowed to Read (full rights) and Write (Except deleting folders and files).

So when I move another folder named 2008-09-01 (which contains some pictures) to the folder Pictures, the ACL should be active for the folder Pictures, the sub-folder 2008-09-01 and the pictures contained in it.
But something strange is happening. I cannot delete the sub-folder 2008-09-01, BUT I can delete the pictures contained in 2008-09-01. How come the ACL is only effective for the folder Pictures, but NOT for the sub-folder 2008-09-01 that was just moved?

Any help would be appreciated.
Thanks!
Simon