Create Intercompany AR Invoice program is not picking Internal Sales Order

Hi,
We have implemented IR ISO from A --> B which is working fine as expected. Even "Create Intercompany AR/AP Invoice" programs are working fine.

Now we are trying to implement reverse IR ISO from B --> A for return of items (it is just reverse to above setup).

For somehow, "Create Intercompany AR Invoice" program is not picking the internal sales order created and would like to see what is main cursor of this program.  This will help us to do reverse engineering of any missing setup configurations.

Thanks,
Srinivas