Install clamd
{{{
emerge app-antivirus/clamav
}}}
Change /home/admispconfig/ispconfig/tools/clamav/bin/clamassassin
{{{
#CLAMSCAN=/home/admispconfig/ispconfig/tools/clamav/bin/clamscan
CLAMSCAN=/usr/bin/clamdscan
}}}
Customize the config files (only changes to files displayed!):

/etc/clamd.conf
{{{
LogFile /var/log/clamav/clamd.log
LocalSocket /home/admispconfig/ispconfig/temp/clamd
MaxDirectoryRecursion 15
User admispconfig
}}}
/etc/init.d/ispconfig_server (auskommentieren von freshclam)
{{{
#        if ps ax | grep -iw '/home/admispconfig/ispconfig/tools/clamav/bin/freshclam' | grep -iv 'grep' &> /dev/null ;then
#          echo "FreshClam is already running!"
#        else
#          /home/admispconfig/ispconfig/tools/clamav/bin/freshclam -d -c 10 --datadir=/home/admispconfig/ispconfig/tools/clamav/share/clamav
#        fi
...
#        array=(`ps ax | grep -iw '/home/admispconfig/ispconfig/tools/clamav/bin/freshclam' | grep -iv 'grep' | awk '{print $1}' | cut -f1 -d/ | tr '$
#        element_count=${#array[@]}
#        index=0
#        while [ "$index" -lt "$element_count" ]
#        do
#          kill -9 ${array[$index]}
#          let "index = $index + 1"
#        done
}}}
/etc/freshclam.conf

{{{
UpdateLogFile /var/log/clamav/freshclam.log
LogSyslog 1
LogFacility LOG_MAIL
OnUpdateExecute chmod -R 755 /home/admispconfig/ispconfig/tools/clamav/share/clamav
}}}

Start the services

{{{
/etc/init.d/clamd restart
rc-update add clamd default
}}}