Actually, I have now given up on Ubuntu installed directly to the HD of my MacBook, and have switched to Ubuntu installed in a Parallels VM instead. There is no wireless issue now, since the Parallels VM provides an Ethernet interface (in software) that can use the Airport wireless NIC of OS X as gateway to the internet.
So, this bug can be closed, unless someone else wishes it to remain open. -- Wireless on MacBook not activated easily... https://launchpad.net/bugs/56892 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs