[Exim] exiscan question

Folks,

I am using exim with exiscan-acl + SpamAssassin, and am pretty happy
with it. However, as I have set it up to reject outright most spam that
is sent (reject score is 5.0), it means it is difficult to tune the
rules. Is there a way to see the spam_report for messages that are
rejected, possibly in the reject log? Alternatively, is it possible to
append rejected messages to a file, without any further mail processing?

Thanks

Ruth