The start of a business process activity flow is not necessarily the service interaction that initializes the business process. You can define your business process to perform some pre-processing activities, perform a database function, or call a Web services; but these activities are not performed until the instance of the new business process is created. The business process is started when an inbound document is received by a notification service that has the initializer property set to Yes. After the business process is instantiated, the process flow activity proceeds in the order specified in the process design.
Note: The first activity in the business process must be connected to the business process IN node.