Translation files

Oke, this plugin is good. Love it!

I made a language .po and .mo file, created the ‘lang’ map in the plugin folder and upload my files in it. In wp-config.php the language is specified:
define(‘WPLANG’, ‘nl_NL’);

How ever, magic fields doesn’t take the translations. It just stays English. I’m just clueless as I can’t figure out what I’m doing wrong.

Hoping for help!