CKFinder and image resize plugin

Hello,

I am using CKFinder with CKEditor. I would like to configure the image resize plugin and pre-defined resize values like:

$config['plugin_imageresize']['smallThumb'] = '90x90';
$config['plugin_imageresize']['mediumThumb'] = '120x120';
$config['plugin_imageresize']['largeThumb'] = '180x180';

I tried to add a new row (in ckfinder/config.php) like:

$config['plugin_imageresize']['customThumb'] = '100x100';

But this does not appear in the resize popup window. Is it so possible to do it? If yes, how can it be done?

Thx for your help.