Extending Business Partner with external ID fields in ECC / EWM

Hi all,

we want to extend our business partner with some external IDs (unique) in ECC  6 / EWM 9.

The idea was to use the Easy Enhancement Workbench (EEWB) for this. Starting EEWB I am told that I should use the Application Extension Tool (AET) which is the replacement tool for EEWB. From what I knew and what I found in SDN / SAP help it seems that AET is only for extending CRM.

Is that right? What is the best way to add 3 custom fields / IDs to BUPA in ECC / ERP? (If we use the customizing for identification types V_TB039 / V_TB039A we would face the disadvantage that there wouldn't be a type check for the IDs entered if I understand that right...)

Thanks for any help.

Best regards,

Stefan