Make HTMLUnit less verbose

I am using HTMLUnit to crawl pages and my log keeps getting cluttered by HTMLUnit output. I.e. It send a whole pages HTML to the log if it returns a 403 status-code.

I tried the following to put it off:

System.getProperties().put("org.apache.commons.logging.simplelog.defaultlog", "fatal"); webClient.setThrowExceptionOnFailingStatusCode(false);

Unfortunately without any effect, my log still looks like a mess. My project uses log4j, but I didn't configure HTMLUnit in any way to use it.