Hi Joey,
normally you would be able to drop the jar-file into the \bin\ext folder, but since the log4j configuration is read before this folder is processed, you will need to manually add your jar to the classpath in soapui.bat.. unless log4j doesn't actually instantiate your layout until after the bin\ext folder has been processed (which is just after the log4j.xml file has been read), in which case you should be able to just put your jar in the bin\ext folder..
Hope this helps!
regards!
/Ole
eviware.com
