Can't paint foliage on an imported landscape

Sorry don’y mean to hijack a thread but seem silly to start a new one on same vein

I would like to create a landsacpe material that has say:

Cracked Rock
Blended
MossCovered Rock

Grass rich
Blended
Grass/dirt patchy

dirt
Blended

The UE 4 macro wrtten for World machine outputs weightmaps: (theres a full spalt and a set of High Mid and Low splatmaps too)
High Angle map
Mid Angle map
Low Angle map

Theres a:
Full Normal
High Angle Normal
Mid Angle Normal
Low Angle Normal

I’m thinking thse could be use to blend a landscape texture that would in general change
to suit the landscape if it was edited at anytime. But I have no found a tutorial to show
how this would be done. I messed my effort up just trying to make a basic material blend

https://www.dropbox/s/aco9u968cdgw7wt/Screenshot%202015-07-04%2000.44.01.png?dl=0