how do I install the qmail-virusscanner

[Ruprecht Helms]

Hi,

is there a good tutorial to install the qmail-scanner. The page linked in qmail.org 
contents only the requirements and the patch QMAILQUEUE. By replacing
qmail-queue after the lines mentioned in the page the setup stops with an
error that it could not find QMAILQUEUE. 

Which files must to be edit to find QMAILQUEUE?
Is there a good virusscanner based on Linux for qmail (good if it easy to
install)?

Regards,
Ruprecht