[logback-user] use logback in OSGi (Felix and karaf)

Hi, My programs are running in Apache Felix with karaf as console. I have changed karaf.sh to provide -Dlogback.configurationFile. In the configuration file, I have a file appender and console. When running, this file appender is created. However, no log recorder is generated either to the file or console. When using in OSGi, what more configuration I need to do? The 3 jars I am using are slf4j-api-1.6.4.jar, logback-core-1.0.0.jar, and logback-classic-1.0.0.jar. Rice