How to set Material of BSP via blueprint

I would like to change the texture of the ground after an event fires from my sequencer.

I currently have a Box Brush created as the ground.

I was able to get a static mesh to change materials correctly, but i want to use the box brush since it works better with collisions. (My actor keep fall through if i convert the brush to a static mesh, evening after setting to BlockAll.)

Is it even possible to change the texture of a Box Brush via blueprint?