[glade--]C++/glame-- basics..

Hi there.
(oh, please cc. to me, I not subscr.)

I got over the first steps to run my own small program.
So far so good, here comes a basic question:

glame-- creates, say, one button and one label.
I'd like to change the label-text when the but is pressed...
so this is the code for the window-class

class mwindow : public mwindow_glade
{
        friend class mwindow_glade;
        void on_but_NewEvent_clicked();
};

and here for the mwindow_glade class:
(snipped)

mwindow_glade::mwindow_glade(
) : Gtk::Window(GTK_WINDOW_TOPLEVEL)
{

   Gtk::Window *mwindow = this;
   Gtk::Button *but_NewEvent =
Gtk::wrap((GtkButton*)gtk_toolbar_append_element(GTK_TOOLBAR(toolbar1->gtkobj()),
GTK_TOOLBAR_CHILD_BUTTON, 0, "New Event", 0, 0, 0, 0, 0));

   Gtk::Label *label_rfreq = manage(new class Gtk::Label("Radio
Frequency:"));
}


how do I access the label_rfreq from the
mwindow class in mwindow.cc ?
I know this is basics, but I'm sure you can help me here.
void mwindow::on_but_NewEvent_clicked()
{
???????
}

thanks a million.
Tobias.