How to chance individual Materials after wrapping in a BP

I imported a device made up of 20 meshes from 3ds Max using Datasmith. I took the DatasmithSceneActor and made an Actor BP from it so I could easily drag it into a scene. Before making it a BP is put all the proper materials on all 20 parts.

Now, having made a BP of it, I can’t figure out how to go in and adjust or reassign the materials. The Material is not visible in ‘Details’ anymore. The Materials aren’t shown in the BP if I open and edit in it. How do I now find, work on and modify the material of individual parts?