Well, the JangaFX forum is very inactive, as most forums seem to be nowadays🤔
So I am entering what I know about masking in this section as well, it might belong under pipeline as well, so I have to figure out how the forum structure should be at it´s best.
But here is the tip on how to make the masks in Lightwave and Blender....
in lightwave you have to use the legacy opengl for the vertex color paint to show up, and exporting from modeler fbx seem to not work properly, so send to layout and export the fbx with the latest file format from there, that should do the trick.
If there is any interest, I might record it for youtube to show the process...