Use Postfix queue id

Hi!

I've made a content filter based on http://www.postfix.org/FILTER_README.html

It's implemented like this:

Code:

smtp      inet  n       -       -       -       -       smtpd
    -o content_filter=spamfilter:dummy

spamfilter unix -       n       n       -       10       pipe
    user=spamfilter argv=/opt/spamfilter -f ${sender} -- ${recipient}

How can i pass the Postfix queue id to /opt/spamfilter?

I've searched through the Postfix docs but i can't find the answer anywhere. I was expecting the answer here: http://www.postfix.org/pipe.8.html

Can someone help me out?

Thank you!