MP3 problem

After buying the ZS-PS30CP I immediately insert a USB stick with two répértires containing MP3 files.
Two problems emerged immediately:
1) The order of the files seemed random.
2) For some files the title in the ID3 tags was "NO TITLE".

For problem 1)
I put a lot of time to try to understand how it classifies mp3 files (I even wrote to Sony unanswered for now). And I still do not know how he does it. What I know:
- Categorized by the file name (not by title or track number in the ID3 tags) files named Track001.mp3, Track 002.mp3 ...
- It does not classify the file name files named: 2010_Bla_Bla.mp3, 2011_Bli_bli.mp3 ...

For problem 2)
I removed all the accents ID3 tags and now it works. I think it is not acceptable for a product sold in France and UTF8 of time, having to go without accents!

If not for the rest it seems to work correctly.