I have found a way to disable the annoying renaming. I found in my guake Python script (in version 0.4.3-3) in lines 996 to 1002:

def on_terminal_title_changed(self, vte, box):

    use_them = self.client.get_bool(KEY("/general/use_vte_titles"))

    if not use_them:

        return

    page = self.notebook.page_num(box)

    self.tabs.get_children()[page].set_label(vte.get_window_title())

As the script shows, /general/use_vte_titles key prevents the autorenaming feature. It is Guake uses GConf to configure his options (explanation). I had to install gconf-editor package to edit Guake options executing sudo apt-get install gconf-editor. Then I executed gconf-editor, I browsed to /apps/guake/general and unmarked use_vte_titles key. Closed the editor. Next time I executed Guake the autorenaming feature was disabled.

Now, all the tabs are named Terminal and if I rename one, it still named all the session with the same name.
It would be helpful to add this key into the Guake preferences dialogue. But this solution worked anyway.