cakephp网站未转换为其他语言

I am working into CakePHP framework.I have to create multilingual site.So I have created to language file.

Step-1 : created two file in app/locale/eng/LC_MESSAGES/default.po and app/locale/spa/LC_MESSAGES/default.po

Step-2 : I have written

msgid "ENGAGE YOUR FOLLOWERS."
msgstr "REALIZAR SUS SEGUIDORES ."

in spanish default.po file. When I hvae change language english to spanish than its not converted into spanish language.

So how can I resolved this problem?

Note :- I am working with CakePHP version 1.3.13