SAP ABAP Table E1VDEWUNB (Header Segment Usage Data) is used by

• Class (1)
• Function Module (2)
• Program (1)

#	Object Type	Object Name	Object Description	Package	Structure Package	Software Component
1	Function Module	ISU_COMPR_INVOIC_1_IN	Baustein zur Verarbeitung eingehender INVOIC_1 IDocs	EE_DEREG_INV	IS-U/CCS	IS-UT
2	Function Module	ISU_COMPR_INVOIC_1_OUT	Rechnung im IDoc Format ISU_INVOIC_1	EECC_EDI	IS-U/CCS	IS-UT