There multiple ways a user can integrate Process with Business Rules in PAM (jBPM) today.

Aside from the Standard BPMN2 Business Rules Task there three more Business Rules Wor Item Handlers:

• org.jbpm.process.workitem.bpmn2.BusinessRuleTaskHandler
• org.jbpm.process.workitem.bpmn2.DecisionTaskHandler
• org.kie.server.client.integration.RemoteBusinessRuleTaskHandler

Each one applies to a specif scenario/use-case. These scenarios are addressed very well in this blog post: https://mswiderski.blogspot.com/2017/04/control-business-rules-execution-from.html. 

Would be helpful to add more details around all the possible ways to integrate with Rules in PAM. The mentioned blog post provides valuable details that in my opinion should be present in PAM Process Development Guide. Things like, parameters (kSession, classLoader, runtimeManager etc) passed to the WIH constructor need to be clarified in the docs.

4.3. BPMN2 tasks in process designer
4.4. BPMN2 custom tasks in process designer