Solution : https://service.sap.com/sap/support/notes/915826 (SAP Service marketplace login required)
Key words :
component component type land_register_number_old relmlrnoold enhance, component component type land_register_number_old bapiupdate enhance, component component type lrnoold relmlrnoold enhance, component component type lrnoold bapiupdate, land register number' field, relevant support package, ddic bapi structure, bapi_re_land_reg structure, bapi_re_land_reg_dat structure, bapi_re_land_reg_datx structure