Umlauts in IMAP Group names

[Tom Rauchenwald]

Hi,

i recently switched an account of mine to imap. 
I can't access some groups on the nnimap-server, and all those groups
contain an umlaut.

They show up like this in the group buffer:

       *: nnimap+gmx:Gel&APY-scht.d-d
       *: nnimap+gmx:Gel&APY-scht.d-u-g
       *: nnimap+gmx:Gel&APY-scht.ruby-talk

but not at all in the server-buffer.

I'm no Gnus-guru, but it looks to me like Gnus does an EXAMINE after the
LIST command on each folder, and this already fails:

19:56:53 61 EXAMINE "Gel&-APY-scht"
19:56:53 62 EXAMINE "Gel&-APY-scht.d-d"
19:56:53 63 EXAMINE "Gel&-APY-scht.ruby-talk"
19:56:53 64 EXAMINE "Gel&-APY-scht.d-u-g"
19:56:53 65 EXAMINE "Entw&-APw-rfe"

61 NO Mailbox doesn't exist: Gel&-APY-scht
62 NO Mailbox doesn't exist: Gel&-APY-scht.d-d
63 NO Mailbox doesn't exist: Gel&-APY-scht.ruby-talk
64 NO Mailbox doesn't exist: Gel&-APY-scht.d-u-g
65 NO Mailbox doesn't exist: Entw&-APw-rfe

To me it looks like the Group name is UTF7-encoded twice somewhere,
because evaluating the following gives me "Gelöscht", which is the
original name of the Group. 
(utf7-decode (utf7-decode "Gel&-APY-scht" t) t)

Can someone give me a hint where to look next, or a tip what's wrong in
my configuration? 

Thanks,
-tom

-- 
Computers are useless.  They can only give you answers.
                -- Pablo Picasso