A customer project must be finished at a given due date.

To schedule a project that must be finished at a given due date, you should use backward scheduling. Backward scheduling is a type of scheduling that calculates the dates of project objects, such as WBS elements and networks, based on their dependencies and constraints, starting from a fixed end date and working backwards. Backward scheduling ensures that the project is completed by the due date and that any delays are identified as early as possible. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html