Add “any” variation order in admin

I would like to create an order in the admin (not frontend) for a variation product that has “any” as the possible choice. I can get most of the way there, but when clicking on “Add meta” to try to add the options, there is no selection of attributes for the product, just a blank meta field into which any value can be put. Is there a way to allow selection of the appropriate attributes in the admin in a similar way to the front end?