As far as I know jBPM does not ship with out of the box DDLs for various data bases.
An option to get DDL is to use hibernate tools (look at JBoss Tools) to generate DDL files for entities that jBPM relies on, same goes for human task server. Once you have DDL, DBA can proceed with schema creation. I believe that regular CRUD access would be most likely enough on runtime to operate.
HTH