There is a timed based start node in jBPM 5
you should find a test case associated with the bpmn in the source tree.
There is a test case in class: https://github.com/droolsjbpm/jbpm/blob/master/jbpm-examples/src/test/java/org/jbpm/examples/junit/BPMN2JUnitTests.java of jpm-example project. The problem is that it doesn't work for me. For you?
But you can define a rule with drools expert to start a process:
rule "start process rule" timer (cron: 0 0 6 * * ?) when then System.out.println("start process"); insert(kcontext.getKnowledgeRuntime().startProcess("receiveMessage")); end