Idempotency configuration in ECC

Hi,

I want to use enterprise service GoodsMovementERPCreateRequestConfirmation_In_V1 within a nonSAP application to post GoodsMovements at an ECC system.

http://es-workplace.sap.com/socoview(bD1lbiZjPTAwMSZkPW1pbg==)/render.asp?packageid=DE0426DD9B0249F19515001A64D3F462&id=…

The service works and I can do all movement types I want.

Now I want to have idempotency activated at the ECC system.

But nobody of the ECC guys knows, what has to be done for this.

What transaction has to be used?

Is there a default value for the time frame for which the system keeps responses for already processed service calls?

If not, I would propose 100 days, because this is the worst case, the nonSAP application could send a message again.

Are 100 days to large for the idempotency time frame of an ECC system?

Regards

Roland