Logging using the asynchronous http client library

Question

How do we configure logging with the Ning Asynchronous HTTP client? There are no pointers in the documentation, except that it depends on Log4J. My project uses log4j and below shows the contents of our log4j.properties file.

log4j.rootCategory=DEBUG, STDOUT
log4j.logger.com.ning.http.client=DEBUG
# Configure the Standard Out Appender
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.target=System.out
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout
log4j.appender.STDOUT.layout.ConversionPattern=%5p (%F:%L) %m%n

I know that the ning apache HTTP client uses slf4j for logging, and therefore we have log4j-over-slf4j.jar in the project path, not log4j.jar. Please, help.

Thanks in advance.