[exim] exim -bh, complete message result

Hi,

a message put through exim with option "-bh" is discarded, as the
documentation clearly explains:

"Messages supplied during the testing session are discarded, and nothing
is written to any of the real log files."

Is there a possibility to retain a copy of the processed message in a
file for later inspection?

Background: I want to take a look to header additions made by
spamassasin (or any other process, e.g. clamav).

Peter