[Vala] Creating constructors on binded classes

["Alberto Ruiz" <aruiz gnome org>]

I have the following class from clutter:

    [CCode (copy_function = "clutter_knot_copy", cheader_filename = "clutter/clutter.h")]
    public class Knot : GLib.Boxed {
        public int x;
        public int y;
        public weak Clutter.Knot copy ();
        public bool equal (Clutter.Knot knot_b);
        public static GLib.Type get_type ();
    }

I don't really know why is it a class, since the structure 
Obviously, in Vala, we want something more natural and comfortable than:
var knot = new Knot();
knot.x = 1;
knot.y = 2;

Since usually, you have collections of several knots, in C you see the use of this class as:
Knot[] knots = {{1, 2}, {3, 4}, {5, 6} ...}

I would like to, at least, provide a simple constructor:
var knots = new Knot[] { new Knot(1, 2), new Knot(3, 4), ...}

The problem here is that if I create a new function, I need to copy paste the whole class, hide it in metadata, paste it on 
clutter-0.4-custom.vala and implement the new constructor. I don't quite like this idea, is it possible to just add the constructor in the custom file without getting the error that Knot is already defined? 
Something like:

namespace Clutter
{
  class Knot {
    public Knot (int x, int y)
    {
       this.x = x;
       this.y = y;
     }
  }
}

Thanks,
-- 
Un saludo,
Alberto Ruiz