Custom widget: creation function.

I have made e gui with glade. It has a custom widget (clase name visor,
class Custom and creation function CWidgetPropio).

Where should I put the creation function? in wich class? I have tried
lots of things (function in the same source file, in the same class that
the main window, etc). I have also try with:

tkWidget *custom_func(gchar *widget_name, gchar *string1, gchar
			*string2, gint int1, gint int2);

But I don't know where should I use this with libglademm.

Thanks a lot!

-- 
Santi <[email protected]>