Comment 17 for bug 951143

b3nn0 script + sami-kankaristo suggestion to disable wake up on lid (/proc/acpi/wakeup) fixed everithing for me. For the latted I addedd in /etc/rc.local:
sudo acpitool -W 16

Shutdown, Restart, Suspend, Hibernate works perfectly both when plugged in or running on battery.

If the hibernate option is disabled/not available for you is likley because of xubuntu policies (i.e. not relatred to 1225B), check here to re-enable: https://help.ubuntu.com/12.04/ubuntu-help/power-hibernate.html

Cheers