--- lib/python/zope/publisher/http.py-orig	2008-07-16 10:46:06.000000000 +0200
+++ lib/python/zope/publisher/http.py	2008-09-03 18:55:44.203125000 +0200
@@ -923,8 +923,8 @@
         '''See interface IUserPreferredCharsets'''
         charsets = []
         sawstar = sawiso88591 = 0
-        header_present = 'HTTP_ACCEPT_CHARSET' in self.request
-        for charset in self.request.get('HTTP_ACCEPT_CHARSET', '').split(','):
+        header_present = 'HTTP_ACCEPT_CHARSET' in self.request.environ
+        for charset in self.request.environ.get('HTTP_ACCEPT_CHARSET', '').split(','):
             charset = charset.strip().lower()
             if charset:
                 if ';' in charset: