[Exim] Exim Filters : mail errors, format queries

I have two questions. Thanks for any help. Rory.

Question 1: Mail Filter Error -- non-local transport
----------------------------------------------------

I have a filter that goes like this on Exim 3.36:

    if first_delivery and $message_size above 5M
    then
       logfile /var/log/exim/size_drop.log
       logwrite "$tod_log From: $h_From: Subject: $h_Subject: \n \t\
                 Sender: $sender_address Size:$message_size"
       mail to it@???
            subject "Oversize mail bounced"
            text "A message from $sender_address to $header_to: with the subject \
            $header_subject: was rejected because it was larger than 5M. The size \
            of the message was $message_size."
       fail text
       "Your message \"$header_subject:\" to $header_to: cannot be delivered \
       because it is larger than 5M (your message was $message_size in size)."
    endif

The mail filter command is not working. The error is:

    Attempt local delivery with non-local transport for >it@???: transport remote_smtp

My message_filter_reply_transport points to the following transport:

remote_smtp:
driver = smtp
hosts = 10.0.0.24
hosts_override

(The Exim host at present is only being used as a pass-through host
doing spam filtering and (now) message size checking. I would be
grateful to know how to avoid this error, keeping in mind that although
"it" is a valid email address in my domain, this user only exists on
10.0.0.24.

Question 2: body of mail sent in fail text
------------------------------------------

Is there a way of removing the part of the body returned in fail
messages? I'm particularly keen to know how to do this when returning
messages that are too large -- a short message simply containing the
fail text is sufficient.

--
Rory Campbell-Lange
<rory@???>
<www.campbell-lange.net>