Maildir as simultaneous spool and backend.

[usenet_spam]

I'm using Gnus v5.11 from cvs'ed emacs 23.  Fetchmail and maildrop
deliver to ~/Maildir like this:

Archives
cur
new
Spam
tmp

The Archives directory contains a bunch of sub-Maildirs:

Commerce
cur
new
Sent
tmp
Ubuntu
(etc.)

I want Gnus to use a single Maildir as both my spool and backend.
Relevant configuration:

(setq mail-sources nil)
(setq gnus-select-method
      `(nnmaildir "localhost"
                  (directory "~/Maildir")
                  (expire-age never)))

All I see in the groups buffer is

       *: nndraft:drafts
       *: nndraft:queue
       *: nnmaildir+localhost:Archives
       *: nnmaildir+localhost:Spam

I don't see my new mail, nor can I find a way to descend into the
Archives directory and see the sub-maildirs within it.  How do I do
that?

Is it okay to use one Maildir as both the 'spool' and 'backend' for
Gnus?  I like to use fetchmail and maildrop to get the mail from my 9
imap and pop accounts into the Maildir, as I like having my mail
local, and can run more than one mail client without worrying about
locking.  I can change around the fetchmail and maildrop configuration
to accomodate gnus, but I'd really rather not have separate spool and
backend Maildirs.

Thanks!