Solution : https://service.sap.com/sap/support/notes/818758 (SAP Service marketplace login required)
Key words :
ecc-dimp-package ist mgv_matnr_lama, business function set dimp, terms long material number, industry solution dimp, business function mgv_lama, business function is_ad_mpn, manufacturer part number, symptom customer exit, long materialnumber, work properly