Hi,
You indeed have to turn off that "simplified breadcrumbs" setting. Once you do that, HikaShop will add an extra "category_pathway" parameter to the products URL when generating them.
Now, this means that if you already have canonical URLs in your products with the "force canonical URLs on listings" setting activated in the HikaShop configurartion, HikaShop won't be generating the URLs since he'll directly use the canonical URLs.
In that case, you would have to empty the canonical URLs using a mass action to have HikaShop regenerate them with the extra parameter.