[gtkmm] Gnome:Glade:Xml - More than one window y one .glade file

[Carlos Ble <carlosble terra es>]

Hi all. Im new in the list. Iam programming with gtkmm and glade using 
libglademm because is a powerful and faster develop platform and i have a 
little question.  I have a .glade file with several windows in it but i can 
get only the widgets from the main window. I try to get widgets from other 
windows and the application stop in runtime saying that it cant find the 
widget. At the moment i can open all the windows by typing the name of the 
windows in the second argument of the Xml.create function:
refGlade_main = Gnome::Glade::Xml::create("main.glade","main");
refGlade_nuser = Gnome::Glade::Xml::create("main.glade","new_user");
(Where main and new_user are windows)
But i can not get widgets from new_user, for example:
button1 = refGlade_main->get_widget("button19",button1);  // this works fine
cancel = refGlade_nuser->get_widget("button57",cancel); // this doesnt work

So the question is ¿should i use a diferent .glade file for every window?
 
Thanks in advance