Custom plugin: Button not appearing in CKEditor

My custom plugin appears at admin/config/content/ckeditor/edit/Full but not at the node edit mode.

Here is my module:

function ion_plugin_ckeditor_plugin() {
 return array(
      'blauer_infoknopf' => array(
         // Plugin name.
            'name' => 'blauer_infoknopf',
            // Plugin description - it will be displayed in the plugins management section of the profile settings.
            'desc' => t('Ein blau hinterlegter Knopf'),
            // The full path to the CKEditor plugin directory, trailing slash included.
            'path' => drupal_get_path('module', 'ion_plugin') . '/plugins/',
            // Plugin buttons definition (optional).
            'buttons' => array(
               'blauer_infoknopf' => array('label' => 'Blauer Infoknopf', 'icon' => 'images/farbe-blau-ipad-wallpaper.jpg'),
            )
         )
      );
 }

And here is the plugin:

(function($) {
 CKEDITOR.plugins.add( 'blauer_infoknopf', {
  init: function( editor )
  {
   editor.addCommand( 'blauer_infoknopf_command', {
    exec : function( editor ) {
     //here is where we tell CKEditor what to do.
     editor.insertHtml( 'Test' );
    }
   });
   
   editor.ui.addButton( 'blauer_infoknopf', {
    label: 'Test-Text', //this is the tooltip text for the button
    command: 'blauer_infoknopf_command',
    icon: this.path + 'images/farbe-blau-ipad-wallpaper.jpg'
   });
  }
 });
})(jQuery); 

The file structure:
.../sites/all/modules/ion_plugin/ion_plugin.module
.../sites/all/modules/ion_plugin/plugins/plugin.js