How do Inverse Battles affect moves that would usually do zero damage?

There's a house on Route 18 in Pokémon X & Y, where you can take part in an Inverse Battle once per day. In this battle moves that are usually Super Effective (eg, Fire -> Grass) are Not Very Effective, and moves that are usually Not Very Effective (eg, Water -> Grass) are Super Effective.

How does this affect match-ups that usually do no damage (eg Normal -> Ghost, or Psychic -> Dark)? Do they still do zero damage, or do they now do Super Effective? If the latter, are there any type match-ups that would do zero damage in an Inverse Battle?

Edit:Turns out I can't read charts.

Your second instinct was correct -- these attacks now do super-effective (2x) damage. There are no immunities added in the inverse battle, so "not-very-effective" (.5x or .25x) is now the worst things can get.

Serebii has compiled the entirety of the inverse type-chart, which you can view here.