[maemo-developers] how to change the language of the program during run time?

[From: mohamed ismael]

hello ,
i am trying to change the language during run time.
i road the documentation of the localization 
http://wiki.maemo.org/Documentation/Maemo_5_Developer_Guide/Application_Development/Maemo_Localization
i generated the *.po file using the command

xgettext -f po/POTFILES.in -C -a -o po/template.po

and then made a en_GB.po copy of the template then made the ar_Ar.po file which contain my localization the i generated 
the *.mo file using the following command

msgfmt po/fi_FI.po -o debian/myapp/usr/share/locale/fi_FI/LC_MESSAGES/myapp.mo

i made the path by hand and run the command so i get myapp.mo file

i added the following line on the main before gtk_init()

                        setlocale(LC_ALL, "ar_AR");
             		bindtextdomain(GETTEXT_PACKAGE, localedir);
			bind_textdomain_codeset(GETTEXT_PACKAGE, "UTF-8");
			textdomain(GETTEXT_PACKAGE);

i added the following line to configure.ac file

ALL_LINGUAS="en_GB ar_AR" 

i built a package and deployed it on N900 device  when  i setup the package
i get the following error

but i run the program with the following command

LANGUAGE="ar_Ar" myapp

the application run and display my language but when i click on a button which contain the following code 

setlocale(LC_ALL, "en_GB");

it does not make any thing .
i have two questions:
1- how to make my program launch with the desired language without the line LANGUAGE="ar_Ar" myapp?
2- how to change the language during run time?

thanks