[exim] exim and amavis talk

Hi,

i'm having a small issue with exim and amavis. So clear: in the messages
do not appear the header refered to the amavis spam analysis (if should
add).

in my amavis config i said that always configure a header for spam
control (somethign like X-Spam-), add a warning if over 5 points and
cutoff if over 12.

I can see in amavis.log that the emails are bein rated. I can see the
puntation but no headers are added to the email. Why?

I'm using standar amavis for exim router and transport and all posible
spam clauses have been activated in amavisd.conf.

Any clues what i'm doing wrong?

Thanks in advance.

jonathan