1. A computer program product comprising instructions encoded on a non-transitory tangible machine-readable medium, the instructions operable when executed by at least one processor to: define a plurality of process components, each of the process components comprising a modular and application-independent package of reusable, granular software implementing a respective and distinct business process, the business process comprising functionality exposed by the process component via at least one service interface, the plurality of process components including: an Inbound Delivery Processing process component that combines tasks concerning inbound delivery processes and enables communication with a vendor and an invoicing process component; a Material Inspection Processing process component that provides services related to quality inspection; a Site Logistics Processing process component that supports preparation and execution tasks concerning internal inventory movement in a warehouse type environment; a Confirmation and Inventory process component that combines tasks required to confirm inventory changes; a Purchase Request Processing process component that provides a request or instruction to the purchasing department to purchase specified goods or services in specified quantities within a specified time; a Purchase Order Processing process component that includes a purchase order business object and a purchase order confirmation business object; a Purchasing Contract process component that handles an agreement between a purchaser and a supplier that details the supply of goods or the performance of services at agreed conditions; a Supplier Invoice Processing process component that includes a supplier invoice business object and a supplier invoice request business object; a Demand Forecast Processing process component that collects demand forecasts for further processing; a Supply and Demand Matching process component that combines the tasks necessary to ensure that sufficient material receipt elements exist to cover material demand; an External Procurement Trigger and Response process component that combines the tasks necessary for processing planned external procurement orders and provides an interface to purchasing from a supply planning perspective; a Logistics Execution Control process component that controls and monitors the supply chain execution activities necessary for the fulfillment of an order; and define a plurality of service interfaces, each service interface associated with exactly one process component and comprising at least one operation, each operation being implemented for exactly one process component, the operations comprising inbound and outbound operations, the outbound operation for a first process component being operable to send a message to a second process component of the plurality of process components, the second process component having an inbound operation for receiving the message, the passing of messages between an inbound and an outbound operation defining a message-based pair-wise interaction between the respective process components of the respective operations, the pair-wise interactions between pairs of the process components including interactions between: the Logistics Execution Control process component and the Inbound Delivery Processing process component, where the pair-wise interaction between the Logistics Execution Control process component and the Inbound Delivery Processing process component includes the transmission of: a delivery request fulfillment request message from the Logistics Execution Control process component to the Inbound Delivery Processing process component, the delivery request fulfillment request message instructions to support the control, triggering, and monitoring of supply chain execution activities associated with a requested fulfillment of an order; and a delivery request fulfillment confirmation message from the Inbound Delivery Processing process component to the Logistics Execution Control process component, the delivery request fulfillment confirmation message containing delivery request fulfillment information associated with a requested fulfillment of an order; the Purchase Order Processing process component and the Supplier Invoice Processing process component, where the pair-wise interaction between the Purchase Order Processing process component and the Supplier Invoice Processing process component includes the transmission of: an invoicing due notification message from the Purchase Order Processing process component to the Supplier Invoice Processing process component, the invoicing due notification message comprising a notification to the Supplier Invoice Processing process component to create or update a reference object to perform invoice verification with reference to a purchase order; and a supplier invoice request invoiced values notification message from the Supplier Invoice Processing process component to the Purchase Order Processing process component, the supplier invoice request invoiced values notification message confirming that a corresponding purchase order is not changed to an amount lower than an already-delivered purchase order if parts of a purchase order have been previously posted; the Purchase Order Processing process component and the Sales Order Processing at Supplier process component; the Customer Invoice Processing process component and the Supplier Invoice Processing component; the Inbound Delivery Processing process component and the Supplier Invoice Processing process component, where the pair-wise interaction between the Inbound Delivery Processing process component and the Supplier Invoice Processing process component includes the transmission of: an invoicing due notification message from the Inbound Delivery Processing process component to the Supplier Invoice Processing process component, the invoicing due notification message notifying the Supplier Invoice Processing process component of the creation of a goods and service acknowledgement; the Purchase Order Processing process component and the External Procurement Trigger and Response process component, where the pair-wise interaction between the Purchase Order Processing process component and the External Procurement Trigger and Response process component includes the transmission of: a purchase order notification message from the Purchase Order Processing process component to the External Procurement Trigger and Response process component, the purchase order notification message providing the External Procurement Trigger and Response process component with notifications from a planning system about postings of goods receipts and the fulfillment of a purchase order; and a purchase order fulfillment notification message from the External Procurement Trigger and Response process component to the Purchase Order Processing process component, the purchase order fulfillment notification message providing the Purchase Order Processing process component with purchase order fulfillment data when new inventories are posted; the Logistics Execution Control process component and the Site Logistics Processing process component, where the pair-wise interaction between the Logistics Execution Control process component and the Site Logistics Processing process component includes the transmission of: a site logistics request message from the Logistics Execution Control process component to the Site Logistics Processing process component, the site logistics request message comprising a request to maintain a site logistics request; and a site logistics request confirmation message from the Site Logistics Processing process component to the Logistics Execution Control process component, the site logistics request confirmation message confirming receipt of a site logistics request message and acknowledging quantities and delivery dates associated with the site logistics request; and the External Procurement Trigger and Response process component and the Purchase Request Processing process component, where the pair-wise interaction between the External Procurement Trigger and Response process component and the Purchase Request Processing process component includes the transmission of: a purchase request message from the External Procurement Trigger and Response process component to the Purchase Request Processing process component, the purchase request message representing a request from a supply planner to a buyer to procure products and/or services for the supply planner; and a purchase request confirmation message from the Purchase Request Processing process component to the External Procurement Trigger and Response process component, the purchase request confirmation message confirming receipt of the purchase request; and store the defined process components and service interface in memory.