To switch jBPM database persistence from the default HSQL embedded database to another database like MySQL, the config file needs updating. (Read installation required software and I suppose that MySQL is installed)

Inside ${jbpm.home}/install update build.xml and ${jbpm.home}/install/jdbc/ to point to the MySQL database. To finish up (make sure you install ant correctly), you have to execute three ant commands from command line inside ${jbpm.home}/install path (you can display all available ant commands typing ant -p): ant create.jbpm.schema, ant load.example.identities and ant install.jbpm.into.jboss in this order.

It should be fine to use JBossAS-5.0.0 or JBossAS-5.1.0 and you should obtain 17 table in your MySQL database.jbpm41_mysql

Note: I have included mysql-connector.jave.jar to /server/lib directory.