Hi guys, I come back with the correct answer. I'm proud to congratulate myself and share with you.

First : the style must not being played (the consequence of this is that it will not be easy to change a setting and realize if it's better or worse) but I don't find out another tips.

Second : Press the 'Key Stop' button (it seems to be working if you use the 'key Start' as well but it seems to me less logical)

From now :
you can press the 'intro/ending' button to reach the settings of the intro1 then end1
you can press the 'Fill' and Arr A button to reach the settings of the Fill1
...etc...

See you soon
Patrick