C4C-ERP Integration: Number Ranges Setup for Account and Contacts

Dear all,

we are in need of clarification on how number ranges actually work when integrating C4C with ERP to transfer Accounts and Contacts. Do we understand correctly that it is not possible to have the same number range within ERP when accounts are created in both C4C and ERP. That in fact one needs an internal as well as an external number range? I have prepared the following slide based on insights I got at the C4C50 training and would like to confirm.

In the training I was quick sure that I got this right but another post I found on this contradicts my understanding. Here it is explained that "a confirmation is sent for the external ID mapping". To my understanding this kind of confirmation is only possible when integration with SAP CRM. In contrast, SAP ERP is not able to to this:

http://scn.sap.com/thread/3527477

Looking foward to your replies.

Thanks and kind regards,

Stefan