Comment 13 for bug 1103593

I've created a workaround until this is fixed:

Creat a textfile 'foo' in directory 'bar' with the following script:
#!/bin/bash
while [ 1 ]
do
 gsettings set com.canonical.Unity.Devices blacklist "['-']"
 sleep 1
done

make it executable

run "crontab -e" from terminal

add a line as follows:
@reboot /path/to/bar/foo