How to set debug flag for artifact?

Hi,

I am trying figure out how to debug a jar file that is built using the artifact in IntelliJ.
I have module A that is using Module B(jar file) and when I am debugging Module A I want to step into Module B.
I have attached the source for module B but I am not sure how I can set the debug flag to true when building the artifact.
Do I need use an ant build.xml file and link it to pre-processing under the artifact menu? If so could you give me an example of such build.xml file?

Regards,
Halldor