Solution : https://service.sap.com/sap/support/notes/882256 (SAP Service marketplace login required)
Key words :
ls_item-itm_type eq lc_limit, ls_item-product_type eq 02, prerequisites program error, header change mode, header view mode, item change mode, item view mode, implementing customer fields, -- service area -->add, co_model_header->pv_freight_extra_pos = 'x'
Related Notes :
| 882363 | SRM50-SUS: Customer enhancement fields in invoice item |
| 762984 | SRM40-SUS: Implementation of customer enhancement fields |