Does anyone have a suggestion?
Currently the Store Manager does not allow to import Supplier Reference into 1.5 and 1.6 PrestaShop versions, however this will be implemented in the next version of the application.
We're planning to release the next version of the Store Manager for PrestaShop in a few weeks.
Thanks for getting back to me.
That would explain why I can't get it to work then!
I'll look forward to the new release.