Comment 4 for bug 465591

I can confirm after changing the entry managed=false in /etc/NetworkManager/nm-system-settings.conf this works expected.

I've marked this as importance=high as it fits one or more of the following criteria:

# Has a severe impact on a small portion of Ubuntu users (estimated)
# Makes a default Ubuntu installation generally unusable for some users
# A problem with an essential hardware component (disk controller, laptop built-in wireless, video card, keyboard, mouse)
# Has a moderate impact on a large portion of Ubuntu users (estimated)

For more information on bugs importance see:
https://wiki.ubuntu.com/Bugs/Importance