[Exim] exim & cyrus imapd & bogofilter

Hello :)

I think this should be a very frequent question but I've searching thru google for the answer and I couldn't find answers.

Im running Exim with Cyrus Imapd and I want to filter the mail with bogofilter.
My local_delivery looks like this:

local_delivery:
driver = pipe
envelope_to_add
delivery_date_add
command = "/usr/sbin/cyrdeliver ${local_part}"
return_path_add
current_directory=/var/
log_fail_output
prefix = ""
suffix = ''
user = cyrus
group = mail

I tried creating a script who run bogofilter and then, pass the result to cyrdeliver (to use it in the 'command' field) but it didn't worked.

Which is the right way to do this?

Thanks in advance