Ok, found it.
It is possible to determinate if a segment is selected checking if the property point.selected is set to "true".

Hi Mikima,

Indeed! I wrote some quick example code for others to see how to find selected segment points.

The following code draws a circle around any selected segment points:

var selectedPaths = document.getItems({
	type: Path,
	selected: true
});

for(var i = 0; i < selectedPaths.length; i++) {
	var path = selectedPaths[i];
	var segments = path.segments;
	for(var j = 0; j < segments.length; j++) {
		var segment = segments[j];
		if(segment.point.selected) {
			var circle = new Path.Circle(segment.point, 5);
			circle.fillColor = 'red';
		}
	}
}

The following code selects and deselects the segment points of selected paths in an even / odd manner:

var selectedPaths = document.getItems({
	type: Path,
	selected: true
});

for(var i = 0; i < selectedPaths.length; i++) {
	var path = selectedPaths[i];
	var segments = path.segments;
	for(var j = 0; j < segments.length; j++) {
		var selected = j.isOdd();
		var segment = segments[j];
		segment.point.selected = selected;
	}
}

thanks a lot!