Edwin,
With all due respect, I think you are not giving JoomlaPack enough credit, or treating it fair.
Version 2.3 (released a week ago) can backup and restore MySQL tables and views natively. It can also backup and restore symlinks. It can even use mysqldump so you can't claim "It does NOT perform a correct backup and is NOT able to backup the shared extension."
It also supports storing and restoring symlinks as such (instead of dereferencing them) so the statement "It also NOT able to perform a correct backup of the files present on the disk" is at least dubious.
I just happened to run across this post while Googling for something else. If you really feel that JoomlaPack lacks certain features which could make it compatible with your extension, why didn't you contact us? We always listen to people and other extension developers. That's how all the JP features found their way from the wish-list to the implemented feature set. I am open-minded and welcome constructive criticism, but I can't guess where to look for it
I would really appreciate a list of problems JoomlaPack causes with JMS-powered sites so that I can resolve them in the next release.
I am looking forward to your feedback.