To add logging on a Plesk-Tomcat 4 server, to a domain name, add the following code to the server.xml file.
<logger className="org.apache.catalina.logger.FileLogger" directory="/home/httpd/vhosts/mydomain.com/tomcat4" suffix=".log" timestamp="true"/>
Make sure that the /home/httpd/vhosts/mydomain.com/tomcat4 directory have the following permissions:
drwxrwxr-x 2 root tomcat4 4096 Aug 8 17:35 tomcat4