Unable to add "datetime" option to a product. Will not save

That pretty much says it all. I can't add a datetime field. I select the option to "assign to product" and get a message that it was saved, but no. It wasn't.

Please help

Well, I managed to rig a way to actually get the "datetime" field to show up in the product: definitely not the way it should be.

Now, I see a date and time, but it's nothing at all like it should be, The date is completely backwards. There is no "time picker" so the user is left typing in a time format that will not make sense to them (and why should it? It's not their job).

So, I need a way to actually add the option to the product the right way,
and a way to change that date format to something usable.