Wish Method to access system overlay in a Service

Erel, I'm basically looking for android capability similar to http://stackoverflow.com/questions/13346111/draw-overlay-in-android-system-wide, but from b4a. I would like to be able to programmatically change whether events are consumed, or passed through to underlying app. Preferably the overlay capability (and perhaps more generically any WM.LayoutParams functionality?) is provided so that it can be incorporated into a service I create.

One example of application in the market which uses similarly capability is https://play.google.com/store/apps/details?id=jp.ne.hardyinfinity.bluelightfilter.free.

I can PM for more details of what I want to do.