[Exim] Too many chars in system filter / 4.30

Hi,

small question: is it possible to increase the maximum number of
chars a system filter can handle?

I got following error when trying to send out mails with a system
filter:

"Error in system filter: string is too long in line XX of filter
file (max = 1024 chars)"


I really would like to have exim letting the system filter generate
mails above 1024 chars.
Is this possible? After searching in the 4.30-spec I found no
runtime variable with which I could set this...

Any hints? Thanks a lot,

Michael