[exim] Valid Chars in Headers of Emails

Hi there.. I have a rule in exim which is below..
I've found out that this blocks Amercian Express Emails as the Subject has:

Subject: Your American Express® Online Statement Is Ready To View
instead of:
Subject:
=?iso-8859-1?Q?Your_American_Express=AE_Online_Statement_Is_Ready_To_View?=

The RFC's says chars like the ® have to be encoded into ASCII in headers or
they are not valid

Has anyone contacted American Express about this before?

Thanks
Craig

deny message       = Message headers contain non ASCII chars
        log_message  = Message headers contain non ASCII chars
        condition    = ${if \
                           or { \
                                {match{$rh_bcc:}{\N[\x80-\xff]\N}}\
                                {match{$rh_cc:}{\N[\x80-\xff]\N}}\
                                {match{$rh_from:}{\N[\x80-\xff]\N}}\
                                {match{$rh_reply-to:}{\N[\x80-\xff]\N}}\
                                {match{$rh_sender:}{\N[\x80-\xff]\N}}\
                                {match{$rh_subject:}{\N[\x80-\xff]\N}}\
                                {match{$rh_to:}{\N[\x80-\xff]\N}}\
                              } \
                           {yes}{no} \
                     }
        hosts       = !+relay_from_hosts