Before-queue integration with Postfix

[Giuseppe Civitella]

Hi all,

I'm trying to integrate Amavis with Postfix as a before-queue filter.
I mainly followed this tutorial:
http://www.postfix.org/SMTPD_PROXY_README.html

Now my SMTP is able to detect SPAM or viruses before queuing emails. But
when it does, it always answers with a 250 to the bounce or discard events:
...
Connected to smtp1.entermail.it.
Escape character is '^]'.
220 *****************************************
ehlo test.it
250-smtp1.entermail.it
250-PIPELINING
250-SIZE 31457280
250-VRFY
250-ETRN
250-XXXXXXXA
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
mail from: <gcivitella at enter.it>
250 2.1.0 Ok
rcpt to: <gcivitella at entermail.it>
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
.
250 2.5.0 Ok, id=28833-06, BOUNCE

As the above mentioned tutorial states:
"When the filter rejects content, it should send a negative SMTP
response back to the before-filter Postfix SMTP server, and it should
abort the connection with the after-filter Postfix SMTP server without
completing the SMTP conversation with the after-filter Postfix SMTP
server. "

So my question is: how should I configure Amavis to get a negative SMTP
response?

Thanks

-- 
Giuseppe Civitella
gcivitella at entermail.it