In jBPM, it is possible to schedule actions to occur as part of the execution of a process instance. However, you can't schedule the creation of process instances, at least not yet.
This feature has been requested in the past (see jBPM Process Scheduling & Monitoring and Programmatically invoking the scheduler) but it is unclear what jBPM should offer in this area. We (I?) feel that the details on how a process is instantiated do not belong to the process definition itself but to the environment where it is deployed. For example, consider you have a predefined schedule for starting processes. Later on you realize sometimes you need to start the process manually to accomodate external events. Further, a manual start might postpone the next programmed start. These requirements would be difficult to capture in a static process definition.
Quartz makes it easy to schedule jobs and execute any custom logic so it is perfect for creating processes. You might also want to think whether the creation logic is a different, encompassing process. The process node allows you to create sub process instances for any process definition. You could have a process whose only purpose in life is creating instances of other process at specified times. It's your call.
Thanks for your answer, I actually have experience with Quartz so I will use that framework for the scheduling of process instances. When I finish it I will try to write a howto, give me a week.
I am new to Quartz (and jBPM), but I would like to use Quartz to kick off jBPM processes. Have you had any luck with this? I'd love to see a copy of the "How-To" you mentioned, if you've had a chance to put anything together.
Any help would be appreciated!