[Dovecot] Visibility of .subscriptions and .customflags

Hi, I upgraded to test65 from 0.99 (mostly to get the namespace feature) and now it seems my .subscriptions and .customflags are showing up as mail folders in my IMAP client (Eudora).

If I try and open those folders, of course I get an error.

How can I configure dovecot so that these aren't displayed to my IMAP client? I looked through about 6 months of acrhives and couldn't find it mentioned anywhere.

Thanks.