if you want STP, then just use nodes, no tasks or states. Normally those have to be persisted.
And besides that, configure jBPM correctly to not use it's own transactions (withseam that is automatically the case afaik)
Thanks for you advice.
All my nodes in the process definitions are plain Nodes and Decisions.
It is still unclear, though, if one EJB3 transaction can span more than 1 node.
All my changes are made persistent as soon as jBPM node finishes, while the next node starts another transaction.