"negative rights" ACLs - working in cyrus-imapd 2.2.12 (FC4)?

[Will Partain]

Folks, I tried to use "negative rights" to do "everybody-but-X"
permissions on a mailbox.  It _looks like_ my "sam" didn't do
anything:

   > lam list.foo
   alice lrswipcda
   bob lrswipcda
   anyone lrswip
   > sam list.foo charlie -rwsip
   > lam list.foo
   alice lrswipcda
   bob lrswipcda
   anyone lrswip

Is something burst, or did I do something wrong?  Thanks,

Will