[Exim] (Exim 3.35) return_size_limit

Hi,

I'm trying to use return_size_limit with Exim 3.35, to stop our server being
used for "bounce spam". (Upgrading to Exim 4 is not an option right now,
although it is on my to-do list).

Is there any way to get Exim to *only* include return_size_limit bytes of
the body in bounce messages, or reduce the buffer size used to create the
bounce? At the moment, even with return_size_limit set to 1, we're seeing
bounce messages reaching up to 9k, which is more than enough to include a
reasonable chunk of spam.

Cheers,

Adam