CGUserDirectory with encrypted FEU-properties

[Freud]

I use CMSMS 1.11.6 with the latest versions of FrontEndUsers (1.21.15) en CGUserDirectory (1.3).

In FEU I have some encrypted properties (lastname and firstname). When I want to list the FEU-members with CGUD I encounter problems with the sortorder (sortby='f:lastname'), the directory-action (with prop='lastname') and the default-action with propval-parameter (like prop='lastname' proval='x%' uselike='1').

I studied the CGUD-modulefiles (action.default.php and action.directory.php) and understand why it's not working well. Because the FEU-propertydata in the database is encrypted, the CGUD-queries pull out data based on that encrypted data.
I've tried several things to get the right data into the arrays $users and $chararray, or modify these arrays with smarty or UDT's, but did not manage to let it work well.

Is there a way to solve this? A workaround or something?
Best way in my opinon would be to decrypt the FEU-data in de CGUD-queries, but I'm not sure if that's possible.