take a look at the jbpm installer. We always use H2 (the new name of hsqldb) to work with jbpm so it's like the default database. The jBPM install is using it. Also you can check a test distribution that I've created yesterday for a workshop in barcelona -> http://salaboy.com/2013/12/10/drools-jbpm-workshop-barcelona-10th-dec-2/ Look at the slides as well that explains how the database is set up.
Hope this helps.