Localizing Pro Sites

I am trying to load the language files outside the plugin folder.
I notice Pro sites is localizing like this:

add_action( 'plugins_loaded', array(&$this, 'localization') );

This way it isnt possible to change the mo-path by calling the load_textdomain_mofile action, ref:

Any chance of changing this action (to forexample init or after_setup_theme), or do you recommend a another way to solve this?