Logging IP adresses of spammer's SMTP

[Thinline Maillist]

Hi,

I'd like to log IPs from "Received" headers to spamd's log file for 
statistics  and further analysis (but only from messages marked as spam).
I tried to modify the code of spamd program, but unsuccessfully, since I 
chose to add it to parse_headers() subroutine, where only protocol 
specific headers are parsed (as it seems to me). This is probably not a 
right piece of source where to place this feature.
I'm not a Perl programmer nor SA expert, so has anyone with more 
experience some idea, how to log spammers remote IPs? Thanks.

Pavel