Thank you very much for your reply!
Unfortunately, this is not what I am looking for but that must be my fault as I am french, I'll try to explain better, sorry!
Basically, I have three child in my scroll view which swipe from right to left with the touch screen. I've managed to center them by adding the class UICenterOnChild and it is working perfectly.
Now I want to add three bullets, not necessarily clickable, underneath to show the user where he is in the scroll view. For example, when the scroll view show the first child, the first button is black and the others are white, etc...
Thanks again for reading and replied to me!
EDIT After hours of research, I found this :
http://befool.co.jp/blog/ayumegu/unity-study-ngui-ScrollBanner/ and the script seems to do the thing with the bullets. Problem is that, from what I understand, the children are scrolling automatically, like a slideshow...