Hi Youval,
When you add UDO data and it is successful, your var response should not be null.
it should return an object type SAPbobsCOM.GeneraDataParams
You can get the object key by
If your UDO is of Document Type :
int DocEntry = response.GetProperty("DocEntry");
If your UDO is of Master Data Type:
String Code = response.GetProperty("Code");
Regards
Edy