After I installed bluez 4.31 and restarted the computer the FN-key did not work. But then I started openSUSE and had to pair the keyboard again with it (it's the same machine and the same bluetooth dongle, but somehow I need to pair the keyboard again every time I switch systems or it won't connect) and coming back to Ubuntu I paired it once more.
And now, the FN-key works, miraculously.
So, perhaps upgrading bluez together with re-pairing the keyboard did the trick, somehow.
A prolific day for posts from me.
I got this working on Intrepid, in the end.
After I installed bluez 4.31 and restarted the computer the FN-key did not work. But then I started openSUSE and had to pair the keyboard again with it (it's the same machine and the same bluetooth dongle, but somehow I need to pair the keyboard again every time I switch systems or it won't connect) and coming back to Ubuntu I paired it once more.
And now, the FN-key works, miraculously.
So, perhaps upgrading bluez together with re-pairing the keyboard did the trick, somehow.