[Vala] Problem using Glade and Vala

[Salvatore Martinico <salvatore martinico tiscali it>]

I wrote this code:

using Gtk;

public void on_bcliccami_activate(Button source)
  {
    source.label="clicked!";
    source.show_all();
  }

int main (string[] args) {     
    Gtk.init (ref args);

    try {
        var builder = new Builder ();
        builder.add_from_file ("gui.glade");
        builder.connect_signals (null);
        var window = builder.get_object ("window") as Window;
        window.destroy.connect(Gtk.main_quit);
        window.show_all ();
        Gtk.main ();
    } catch (Error e) {
        stderr.printf ("Could not load UI: %s\n", e.message);
        return 1;
    } 

    return 0;
}

I compiled it with "valac --pkg gtk+-2.0 --pkg gmodule-2.0 main.vala  -o
GladeExample".
But when i click on button of my application callback method is not
called!  Why?
I use Vala 0.10.0.
I attached my glade file.

Attachment: gui.glade
Description: application/glade