Hi Maria,
I'm not very familiar with Ibase management, but it seems that you are talking about adding a product to an ibase... and product do not have to be enhanced with Z fields (as we usually do it through customer includes for example). Instead, you need to create settypes and assign them to the corresponding product category: all products belonging to this category will automatically inherit those attributes. See:
SAP Library - Product: CRM - Object Extension
Best regards,
Nicolas.
