Status of Sales Order not changing

Dear Gurus,

Our client's document generation process is that they make a Sales Order for say 100pcs to their Dealer and then the Dealer wants the client to send them 20pcs on a perticular day. To inform the Plant to dispatch 20pcs to the Dealer on that day, client makes another Sales Order (referencing the first Sales Order) for 20pcs on the day of requirement, which the Plant accordingly dispatches after VL01n and VF01.

Now the issue is since we are referencing OR doc type with another OR doc type, system is not changing the status of the first OR even after complete reference, but the second OR is changing to 'Completed' after full referencing to an OBD.

I checked all the combinations but it is not changing. I tried many combination in VTAA for OR to OR and also in VOV7 for diff combinations of Completion Rule.

What else can I do? Kindly help me out here, for which I will ever be greatful.

Thanks and regards

Venkat - Hyd