The request you've linked is still on our customer wishlist but has not been implemented yet unfortunately. We've added you to the list of customers interested in this addition. Unfortunately, though, as we have over 10 000 customers we do need to prioritize new features based on a lot of factors. At this moment we don't have an estimated release date for this functionality.
As a workaround, to at least get the data into your database, you could use one of the asset custom fields in the import template for this. Asset custom fields can be configured under Configuration\Asset Pages.