Some Business Application Programming Interfaces (BAPIs) allow customer enhancements using an enhancement structure. This structure contains only some keys to which customers can add their add-on fields via append. The data contained in this structure is then moved from or to the generic BAPIPAREX structure. The BAPIPAREX structure itself is only a character container. The BAPIPAREX structure (not the enhancement structure) then becomes part of the IDocs. If the Segment Type is BAPIPAREX, you specify the name of the enhancement structure in this field. The enhancement structure then also automatically becomes the maintenance structure of the IDoc editor. Therefore, it is not possible to specify a maintenance structure in this case. As result, you will be able to use the enhancement structure to see and maintain your add-on data.