Gnus can't handle maildir groups with a space in the group name

[Tassilo Horn <tassilo@member.fsf.org>]

Hi all,

I've switched from nnimap to OfflineIMAP, and it works quite nice.  But
there's one problem.  Gnus doesn't see the (maildir) groups that contain
a space in the group name, like

  INBOX.Junk Mail
  INBOX.Sent Items

My config is as follows:

(add-to-list 'gnus-secondary-select-methods
             '(nnmaildir "Fastmail"
                         (directory "~/Mail/Fastmail")))

~/Mail/Fastmail is where all nnmaildir groups reside.  I think this is
the right way to use it, right?

Is there something I can do that gnus can see those two groups?

(I know I can fiddle with OfflineIMAP and provide a customized group
name to maildir folder translation somehow, but I don't see a reason why
Gnus should fail with maildir groups with whitespaces.)

Bye,
Tassilo