UE5 - Landscape paint layers + world partition?

I imported a landscape into a map with World Partition enabled, but there seems to be no option for exporting or importing the paint layer masks there.

If I import the terrain as a single heightmap with no partitioning switched on then I do get those options back.

So what is the intended workflow now for terrain + world partition. I noticed that exporting the heightmaps exports them as tiles instead of one large heightmap so will this work the same for paint layers? And if so is it simply not implemented yet or is there something I’m missing?