DrawStyle::LINES ignored

I want to create a grid on the floor using the following function. For
test reasons I also create an SoSphere object inside this function.

My idea for the grid is a square with the drawstyle set to LINES. The
square is generated as SoFaceSet.

My problem is: I can see both sphere and square, but FILLED and the
material color is also ignored.

SoSeparator* tOIRobotViewerXML::createGrid()
{
	SoSeparator *result = new SoSeparator;
	SoCoordinate3 *vertices = new SoCoordinate3();

	SbVec3f points[8];
	points[0] = SbVec3f(-4000, 0, -4000);
	points[1] = SbVec3f(4000, 0, -4000);
	points[2] = SbVec3f(4000, 0, 4000);
	points[3] = SbVec3f(-4000, 0, 4000);

	points[4] = SbVec3f(-4000, 0, -4000);
	points[5] = SbVec3f(-8000, 0, -4000);
	points[6] = SbVec3f(-8000, 0, -8000);
	points[7] = SbVec3f(-4000, 0, -8000);
	vertices->point.setValues(0, 8, points);

	SoFaceSet *fs = new SoFaceSet();
	int32_t values[] = {4,4};
	fs->numVertices.setValues(0, 2, values);

	SoSphere* sphere = new SoSphere();
	sphere->radius = 1000;

	SoDrawStyle *drawStyle = new SoDrawStyle();
	drawStyle->style = SoDrawStyle::LINES;
	drawStyle->lineWidth = 1;
	drawStyle->linePattern = 0xaa;

	SoMaterial *material = new SoMaterial();
	material->ambientColor.setValue(.33,.22,.27);
	material->diffuseColor.setValue(.88,.57,.11);
	material->specularColor.setValue(.99,.94,.81);
	material->****niness =.28;

	result->addChild(vertices);
	result->addChild(fs);
	result->addChild(sphere);
	result->addChild(drawStyle);
	result->addChild(material);

	return result;
}