Problem with traslate (Reader plugin)

Hello,

I have translated to Spanish with poedit Reader plugin. I've uploaded to my server in plugins/reader/msreader-files/languages but ignores the translation. I've gone as default.po and default.mo. By not running as I have again come up with the name: wmd_msreader_es_ES.po y wmd_msreader_es_ES.mo. Any idea why the translation does not work?
Thanks.