How to copy ringtones to Galaxy Ace 2?

*Gingerbread on board :-).* I try to customize ringtone, so I copied files to "/system/media/audio/ringtones". Depending on the app, either the copy is forbidden or the copy is ignored. Next try -- as with Galaxy Ace, I created directory "/mnt/sdcard/media/audio/ringtones" and copied the files there. This worked, however Android does not pick them up when selecting audio for a ringtone. When I first customized my phone (around 2 years ago) I used the app "Tone Picker" to help the system to select the customized audio, maybe something was changed in the app, I don't know, however this also does not work. I would prefer to copy somehow the files without need of external application anyway. So how to do it?