I've just realized that.
I think I found a way...Looks rather stupid, but it may work.
I've tested how to do it with javascript. Ok. It works.
So, If I have a pre-prepared file with all the js and during my program runtinme I generate js lines like
new google.maps.LatLng(37.772323, -122.214897),
new google.maps.LatLng(21.291982, -157.821856),
new google.maps.LatLng(-18.142599, 178.431),
new google.maps.LatLng(-27.46758, 153.027892)
..
..
..
then insert them in the correct place in the pre-prepared file, I would end up with a file with all the coordinates I want.
then I save this file as HTML
Then firing the webview window with this local html file, shoud give me the result I want.
In theory at least...