(setq html-helper-timestamp-hook
      (lambda ()
	 ;; The trailing four spaces cause html-helper-timestamp-end
	 ;; to be indented correctly (kludge).
	 (let ((time (current-time-string))
	       (zone (nth 1 (current-time-zone))))
	   (insert "    <meta http-equiv=\"Last-modified\" content=\""
		   time " " zone "\"/>\n")
	   (insert "    <meta http-equiv=\"Expires\" content=\""
		   time " " zone "\"/>\n    "))))

;; format-time-string is a function, not a variable
;; don't add hooks with setq, use add-hook
;; don't add lambdas to hooks as a general rule, it can get messy later.

(defun html-helper-deutsche-timestamp ()
  (insert (format-time-string "    Letzte Änderung:  %d. %m. %Y")))

(add-hook 'html-helper-timestamp-hook 
	  'html-helper-deutsche-timestamp)

(setq format-time-string "%C") 
(setq html-helper-timestamp-hook
      (lambda ()
         ;; The trailing four spaces cause html-helper-timestamp-end
         ;; to be indented correctly (kludge).
	(let (time (current-time-string))
           (insert "    Letzte Änderung: "
                   time".")
                   )))

(setq html-helper-timestamp-hook
      (lambda ()
         ;; The trailing four spaces cause html-helper-timestamp-end
         ;; to be indented correctly (kludge).
         (let ((format-time-string "%d. %m. %Y")
	       (time (current-time-string)))
           (insert "    Letzte Änderung: "
                   time".")
                   )))