The kernel may not move between two versions.
I think the version should be based on petals-esb-container and not on petals-esb-kernel. So, #1 too.
As a reminder, the container version is independant of the distribution version (4.0.1).
This is indeed complicated... But users only need to know about the distribution version. Kernel, container and component versions are only relevant for the development team.
Fixed in trunk