[Dovecot] how to store flags \Seen into read-only mailbox?

[seriv at parkheights.dyndns.org]

I was looking for workaround, and tried to use one uid for all users, and ACL plugin to give permissions like:
---
owner lrwstiekxa
anyone rls
---
rls should mean read, lookup and write-seen. 
Read and lookup works, and as soon as I remove these letters I can't read mail folder. 
But 's' is not working, I'm getting the same:
---
7 OK Store ignored with read-only mailbox.
---
in rawlogs

I can not find a way for users to keep their own track of what messages have been \Seen in read-only shared folder. 
-- 
  Sergey Ivanov.

----- seriv at parkheights.dyndns.org wrote:

> This problem is apparently about changeset
> http://hg.dovecot.org/dovecot-1.1/rev/eec74a6ad62e.
> This change makes dovecot behaviour different from what is described
> in wiki, about sharing and making private /Seen flags, 
> see http://wiki.dovecot.org/SharedMailboxes?highlight=(flags are
> shared or private)
> When I've tried to revert it, first time with my client it worked
> perfectly.
> But then clients were not able to open any mail folders, and imap
> processes were dying.
> -- 
>    Sergey Ivanov.