HowTo Disable Logging Output for classes using commons.logging

Hello,

I use log4j-1.2.8. In my new project I use quartz. Quartz gives me a lot of
logging messages that I don't need. It's especially dangerous because
It writes all of this output to the log file of the server. 

I would like to get rid of this. The logging of quartz uses commons logging 
which can be manipulated through log4j says this resource:

http://jakarta.apache.org/commons/logging/guide.html#Configuring_Log4J

So I modified my log4j.properties in this way:

log4j.rootLogger=INFO, logfile,cons
log4j.appender.cons=org.apache.log4j.ConsoleAppender
log4j.appender.logfile=org.apache.log4j.RollingFileAppender

log4j.appender.logfile.File=/usr/local/log/accounts.log
log4j.appender.logfile.MaxBackupIndex=5

--> log4j.logger.org.quartz=ERROR
log4j.logger.org.apache=ERROR
log4j.appender.cons.Threshold=INFO


But still I get the INFO messages in the server log. What do I have to do?

Cheers,
Pete