Hello,
Yes what you try to do is possible. It seems fine to me as we do a similar functionality for orchestration purposes of our systems, so there no sign of a workflow/bpm engine working in the core while using the system. In the meantime we get all the advantages of jbpm within our system i.e. model our systems, real time customisation, loosely coupled integration with other systems/services - soa etc.
Check out the following link,
https://community.jboss.org/people/bpmn2user/blog/2011/11/14/jbpm5--local-human-task-example
also check out the bpmn2user's blog in general,
https://community.jboss.org/people/bpmn2user/blog/
I recomend it! it is really valuable with great resources.