I did jsut as Marius explained later in this thread, but he used an example of hourly format only (when mp3u file names contain only an hour and letters a, b, c etc. In my case the full name of the file is like this: 2016-02-29-10a
So in order to make RDJ take the right file each time, I created a test event with a task "Load m3u Playlist by a Date Mask". In the "argument field" I wrote YYYY-MM-DD-HHa, (in other cases YYYY-MM-DD-HHb and YYYY-MM-DD-HHc - it depends on a number of a commercial break in an hour).
I am not a programmer, I am a music editor, so, I am not sure if I put it down right.
It didn't work anyway.
I added all the audio files into the RDJ library, in case you might think I've forgotten this.
So what might be my mistake?
Thank you very much!