Posting change notice in SAP via Interface

Dear Experts,

Our client is currently using SAP WM. We are thinking of implementing ASRS(automatic storage and retreival solution) via a third party software. SAP WM is used for creating SU numbers and keeping count of stock figures at bin level and all major decision making(Putaway & picking locations) and processing happens at the ASRS system

SAP WM contains stocks of pallets as storage units. each SU is one pallet. These SU's are generated when goods are produced and made accountable in SAP IM/WM level and then passed on to the ARSR system where this system identifies best location and places stock into available position via interfaces and also when the pallets are retrieved from ASRS they are interfaced back to SAP WM system.

The requirement is as below:

It is quite possible that ASRS system cannot retrieve few pallets from their current positions. In such cases ASRS system sends information back to SAP that the SU is not available. In such cases there is a need to create posting change notice for these SU's in SAP IM/WM and block the stocks in the SAP system for such SU's.

Question:

1. Is it possible to create Posting change notice and post stocks to blocked status at IM/WM level in SAP via blocking message received from interface from third party system?

2. Which Idoc type should be used for this scenario?

3. is there a standard FM available that can handle the above scenario and post the stocks in SAP system upon receiving blocking message from ASRS system?

If anyone is using the above scenario and can provide inputs in this regards it will be quite helpful to us.

Best Regards,

Harish