[exim] Headers with newlines and system filters

Hi,

I have a rather interesting problem and was wondering if anyone on
this list could help me.

I have a system filter which is matching a subject line, re-writing
the subject header and delivering to an additional recipient on
successful match . This filter works for most mails, however some
mails with longer subject lines fail the filter regex.
At first I thought this was just a limitation in my regex but couldn't
find anything wrong, infact running the test through exim -v -bF was
sucessful. Then I realised the orginal mail had a \n\r in the subject
header so it was on two lines. I tried to match these in my regex but
exim ignores the wrapped line after the subject header line.

Is there anyway to make exim concat multi line headers or make the
regex match multi line headers.

Exim version 4.43-1

Thanks in advance

--
Kind Regards,

Eroteme