Why is vertex masking so poorly documented, no decent tutorials

Bumping this one,
No one seem to be able to answer on it, or another users question on this matter, I´ve been trying for months (from time to time) with the masks in embergen, just guessing it could use blender painted vertex maps, or weightmaps , can´t find a single video tutorial on it that indicates there is some showcase on it in the video.

It´s the very basics…in blender 2,79, I can paint in a weightmap on a head for instance, use that as emission for the fluids inside of blender with its fire and smoke fluids, dead easy and great.
Now surely it must be a way to use either a Weightmap, or vertex map on One single mesh as the fluid emission inside of embergen, I don´t expect embergen to have a brush paint tool in there at this stage, but surely the ability to emitt from painted weightmaps, or vertex maps only.

Now I have mostly tested on fbx exports, but also alembic, no difference.
Ivé managed to get a fluid emission on for instance two seperate spheres in the same fbx, but I don´t think that had to do with the actual paint I did.

My question was made in december 21, still no one responding with a yes or no, or anything at all, and same with this guys question…

Blender Alembic Vertex Color - Software Support & Suggestions / EmberGen - JangaFX Software Forum