Why are classes are not loaded from ProcessClassLoader in jBPM 3?

Issue

We are having an error related to class loading in the context of a jBPM process action handler. The action handler uses a utility class Foo, which is loaded from the UnifiedClassLoader, and not from the jBPM process. The Foo class is deployed to the jBPM database along with the process definition, and should thus be loaded by the ProcessClassLoader. Unfortunately. the Foo class is also contained in a *.jar file that is somewhere in the app servers class path.

In our production environment, we can't scan the complete app server to ensure that a class is not already contained in some deployment. We need to have it loaded by the ProcessClassLoader if the class was deployed with the process definition.