Hi,
So, I have made some tests, with several ACL configurations and I saw a potential problem with the file upload.
I think that was the source of your problem.
I was wrong when I said that you have to save the product. The files and images are automatically assign to the current product, so saving is not required.
I would send you a new package when my other tests will be finished.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.