I have published a very small article to help one in starting a process (modeled by using the BPM tool in NWDS) once it has been deployed into the Application Server.
Here is the link to the article -http://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/80ace13d-5182-2b10-a584-bfa204206...
In the article, I have mentioned about how to start the process from an Application. Also given is a brief set of steps to start the process from the wsnavigator and from the nwa portal directly.