Hi GHAZI,
When I was evaluating JBPM different version then for some time I had done POCs on JBPM4.4 but now I'm not working on version 4,I'm using JBPM5.
But as I remember one detailed document was there.Here is the link for your reference.
http://docs.jboss.com/jbpm/v4/userguide/html_single
Thanks,
Anand