Paint Procedural Placement masks with code

[Knowen]

Hello everybody,

with the following code we are able grab the farmlands infoLayer and paint on it.

local infoLayer = getInfoLayerFromTerrain(terrainNode, "farmlands")
    if infoLayer == nil or infoLayer == 0 then
        printError("    Could not find farmlands info layer")
        return
    end

As I figured out how to use Procedural Placement (PP) on a 16x map without crashing the GE, I wonder if it is possible to also paint fields (or anything else) to the PP masks with code. I wasn't able to find anything to it but maybe here are some smart folks. 

Thanks in advance

Knowen