Custom apache log files

[-ck-]

I wish to create custom log files to allow Urchin to track and report statistics correctly utilising UTM. For this to work I need to add

\"%{Cookie}i\"

to the log file.

I have edited /etc/httpd/conf/httpd.include to include the information, but this will be overwritten any time Plesk is updated.

I know I can add a custom conf file to

/home/httpd/vhosts/<domain-name>/conf/vhost.conf

but I don't want to mess up any of the Plesk custom reports already defined (plesklog).

What's the best way to add \"%{Cookie}i\" to all my log files (for 65 domains)?

Thanks,

Christiaan