S4S not importing DDS normal (bump) for walls?

Hi. I'm making some walls and I have to change the normal maps. I'm used to making normals using DDS and I need the alpha layer. So I've made the normal for my walls and saved as DDS "DXT5 interpoladed alpha", as always, but Studio won't recognize my file when I go into import. I can export as DDS, but not import. I have the latest version of Studio (Harmony 3.0.1.9).

I searched for this in the forum and couldn't find anything, except for the update notes saying that DDS was being supported again? I'm a bit confused, though.
Is this something that can be fixed or is Studio not supporting DDS files anymore?

Thank you!