If you take a look at the jBPM hbms, you'll see that the id generator is set to 'native'. According to Hibernate doc, this means that indeed only one sequence will be used...
You can change this by changing the hbms of jBPM.
See http://www.hibernate.org/296.html for more information.
Thanks jbarrez. I am aware I can change it but the question is
will changing the model to use multiple sequences have any adverse affects in jBPM
I don't want to get any unexpected behavior like I did with OSWorkflow
I haven't tried it yet, but I don't see any problems. After all, Hibernate will handle the primary key for jBPM and I don't see any problems in that.