Return PO Process AFS

Hello Sappers,

I trying to create a new process to return goods to vendor using a return purchase order in AFS.

I would like to know if somebody already uses a similar flow.

I already created a new document type but I have a problem when creating outbound deliveries through VL10B because the system gives an error about "Allocation Run". The message is:

"ARun type does not exist"

May you help me with some advices, please?

Have I to setup some customizing in SPRO for allocation run?

Have I to setup some customizing for following step? (Deliveries,...)

Thank you,

Lorenzo