For JBoss-3.2.0 the configuration goes as follows:
Copy the proper database description file from "<JBoss-dir>/docs/examples/jca" to the deployment directory of your configured JBoss profile (for example "<JBoss-dir>/server/default/deploy") and customize it.
Restart JBoss
After that, the running JNDI 'nodes' can be checked using the JMX-Console (http://localhost:<port>/jmx-console), using the "listXML" operation. In my case, I had an entry saying
--- listXML results --- java: DB2DS org.jboss.resource.adapter.jdbc.WrapperDataSource --- /listXML results ---
From this I could easily derive the correct JNDI-name, which I configured as:
--- dbforms-config.xml --- <dbconnection id = "1" isJndi = "true" name = "java:DB2DS" default = "true" username = "user" password = "password" connectionProviderClass = "org.jboss.resource.connectionmanager.LocalTxConnectionManager" conClass = "COM.ibm.db2.jdbc.app.DB2Driver"/> -- /dbforms-config.xml ---