Hi.

Small, works. After that you are in a mail with the correct command
inserted. Remove everything crm114 shouldnt see, as usual. Sent
it. Finish, it learns. :)
(Sure, one can do a similar thing for the command line interface, but
as my mail reader and server are on different hosts i use the mail
command interface. :) )

(defun jj-forward-spam ()
  (interactive)
  (gnus-summary-mail-forward 1)
  (message-goto-to)
  (insert "joerg@ganneff.de")
  (message-goto-body)
  (let ((ans (completing-read "Spam / Nospam? "
                              '(("s") ("n"))
                              t nil nil)))
        (cond ((string= ans "s")
                        (insert "command password spam"))
                  ((string= ans "n")
                        (insert "command password nonspam"))
                  (t
                   (error "Invalid choice.")))))
(add-hook 'gnus-summary-mode-hook
          (lambda ()
            (local-set-key (quote [f6]) (quote jj-forward-spam))))