[Exim] how exim 3.2 handles non-dels with attachments

hi there

we still use exim 3.2.

How do I find out, what exim does with a rejected email
(incl. attachment) exactly.

Does it returns the whole attachment? or doesn't it? The
only thing I could find out in the config-file was the
limitation of the return-size of an email (10K). Or an
other thing I did is sending an email with an attachment,
to see that the email is returned incl. attachment. But I
could not find the config in the config-file.....

Has anybody an idea/tip where to look?

thanks
bh