I'm trying to use a custom Appender with Logback under a WebSphere 6.1
application, but am failing upon Logback configuration with a
ch.qos.logback.core.util.DynamicClassLoadingException, caused by a
java.lang.ClassNotFoundException .

A search on this mailing list for "DynamicClassLoadingException" returned 0
results, and neither the documentation nor Google were of any further help.

Here's my setup:
EAR:

• logback-classic-0.9.9.jar
• logback-core-0.9.9.jar
• slf4j-api-1.5.0.jar
• ...
  WAR (configured to PARENT_LAST):
• logback.xml
• com.ziesemer.test.TestAppender

I will attach the stack trace / STDOUT, as it is a bit lengthy (141 lines).