Hi,
It can be done by editing the "hikashop_product.xml" file in the "yourSite/administrator/components/com_joomfish/contentelements/" folder.
In this XML file, add a field "product_published". Then in the JoomFish interface, it can be possible to change the value of this field to display or not the product depending on the language.
Example of the line to add in the XML:
field type="text" name="product_published" length="1" maxlength="1" translate="1">
Product published
</field>
Then set 1 to publish in the language or 0 to unpublish.