link PPDS orders with pegging in APO

Hi

The requirement is that for a certain finished product with a bom component (semifinished) and PPDS orders should be linked each other, which means if I reschedule a semi order then the finished product order should be automatically rescheduled accordingly keeping the same interval. The business process is that a finished product order is created either manually or with heuristic and then run heuristic at semi product level to generate the pegged order for that. I once saw this scenario somewhere and it was working exactly as expected in that project but it is not case for now. What can be missing in the configuration or master data? Any input would be appreciated

klif