Default [Q] defy+ ringtone import fails

I use a Defy+ (MB526) with CM10 (Android 4.1.2) 20131030-nightly.
I tried to import ringtones from my Defy (.ogg-format) copying them into the /system/media/audio/ringtones folder giving them the proper rights.
Even after restart they are not visible in the ringtone selection menu.
Also when trying to use ringtones via sdrescan (reading them from SD-Card) no selection is possible.

Does anyone have an explanation or solution ?
Help would be appreciated.