Dear Nicolas
Thanks for your location of script, i found that the insert script for hikashop_vm_product using vm_product_sku as key whereby VM3 sku is not a neccessary field
i genarate a random number to all product in virtuemart sku using below
UPDATE `prefix_virtuemart_products` SET `product_sku` =
(SELECT concat(
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' ),
ELT(FLOOR(1 + (RAND() * (50-1))), 'a','b','c','d','e','f','g','h','i','j','k','l','m ','n','o','p','q','r','s','t','u','v','w','x','y', 'z',
'A','B','C','D','E','F','G','H','I','J','K','L','M ','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z' )
)
) WHERE product_sku="";
However, after the import all product image are showing barcode.png
still finding out and would be appreaciate if you can highlight the cause