Bruno,
The details of every project are so different from one another, that a tutorial on how to port your app from MyEclipse to Ant wouldn’t be any more helpful then a basic tutorial on how to write an Ant script.
To make a comparison, as we know Ant is like Makefile, so this is would be like having a large KDE application, and asking a kernel developer for a tutorial on how to write a Makefile… they might just stand there for a minute and then reply that the two make files are so different, there isn’t really anything he can provide to you to make it any easier.
I have added you guys to the internal enhancement request we use to track this though.