I am not sure exactly what you are asking. As far as I know, jBPM 5.4 does not use any kind of databse by default, not even H2. I think the human task service uses H2, but the jBPM engine itself does not. Now, that said, I've read it is possible to get it to use a database, but have not figured it out yet. Some discussions and articles I've read talk about doing persistence through the JBPMHelper class.
Post back here if you get it working.
User guide clearly states all the steps required.section 3.7. If you are facing issues, errors then please post the stack trace.