how to get the information of the vertices from a Primitive in Away3D 4.1

const geom     : PrimitiveBase   = new PlaneGeometry(100, 100, 10, 10),
      vertices : Vector.<Number> = ISubGeometry(geom.subGeometries[0]).vertexData;
       
for (var i : int = 0, l : int = vertices.length; i < l; )
{
    const 
        // position
        vx : Number = vertices[i++],
        vy : Number = vertices[i++],
        vz : Number = vertices[i++],
        // normals
        nx : Number = vertices[i++],
        ny : Number = vertices[i++],
        nz : Number = vertices[i++],
        // tangents
        tx : Number = vertices[i++],
        ty : Number = vertices[i++],
        tz : Number = vertices[i++],
        // primary uv
        pu : Number = vertices[i++],
        pv : Number = vertices[i++],
        // secondary uv 
        sv : Number = vertices[i++],
        sv : Number = vertices[i++];
}