--- lisp/textmodes/flyspell.el
+++ lisp/textmodes/flyspell.el	2009-03-31 16:46:41.440001521 +0200
@@ -263,6 +263,12 @@ If `flyspell-large-region' is nil, all r
   "The key binding for flyspell auto correction."
   :group 'flyspell)
 
+(defvar flyspell-signature-separator
+  (if (boundp 'message-signature-separator)
+       message-signature-separator
+     "^-- $")
+  "*String used to recognize .signatures.")
+
 ;;*---------------------------------------------------------------------*/
 ;;*    Mode specific options                                            */
 ;;*    -------------------------------------------------------------    */
@@ -298,7 +304,7 @@ property of the major mode name.")
 		      (point)))
 	(signature-begin (save-excursion
 			   (goto-char (point-max))
-			   (re-search-backward message-signature-separator
+			   (re-search-backward flyspell-signature-separator
 					       nil t)
 			   (point))))
     (cond ((< (point) header-end)