LXC 0.7 is available as an upgrade in Gentoo Linux. After you get it you may have a surprise… no console output after lxc-start. It seems it is not a bug but a feature :) (as always with software). To get back the output just add -s lxc.console=$(tty) to the command line, like:

# lxc-start -n machine_name -s lxc.console=$(tty)

It does not look 100% like before but at least you get some feedback and are able to login. And it seems the shutdown does not work as well as expected (this has to be investigated over weekend).

This is fixed in 0.7.1

Update The poweroff now works and it stops the container as well. Nice job :)