[xwiki-users] Redirecting logs to a file instead of console on tomcat?

I have gone thru http://platform.xwiki.org/xwiki/bin/view/AdminGuide/Logging. As per logback.xml(inside in MyApp/WEB_INF/classes), looks like it relies on the fact that container will redirect all the console to logfile automaticcaly. But it is not happening. I am using tomcat 6. i want to put all the possible logs i.e log.info.log.warn,log.error,log.debug,log.fatal inside log file For logging i am using below code snippet private static final Log log = org.apache.commons.logging.LogFactory.getLog(AuthServiceImpl.class);// declared as insiance variable under AuthServiceImpl.class then in my public method i am doing the logging as log.error("Testing AuthServiceImpl Reply = "); But its printing the logs on tomcat console. Guys really i have no idea how to print the to file instead of console.Inside logback.xml(inside in MyApp/WEB_INF/classes) i can see below setting. I have really no idea what is happening? Thanks in advance.