memoryEntryPoint is retrieved as null, what could be wrong here or do I need to do some special configuration in order to use working memory point streams?

            StatefulKnowledgeSession knowledgeSession = GivemeStatelessOrStateful

                        .getStatefull("cashflow.drl");

            WorkingMemoryEntryPoint memoryEntryPoint = knowledgeSession

                        .getWorkingMemoryEntryPoint("TransactionStream");