TwinView option disabled in Nvidia-Settings

I am trying to configure dual monitors on my Ubuntu hardy however the 'Twinview' option is disabled in my settings. To enable this option you would have to tweak the 'xorg.conf' file. First of make a backup of the current '/etc/X11/xorg.conf' so you can always revert to this copy. Here are the instructions to modify the file to enable 'Twinview'

- sudo gedit /etc/X11/xorg.conf
- Search for line which says "Twinview" "0". Change the "0" to "1"
- sudo nvidia-settings (now the nvidia driver should automatically detect the second connected screen)

In looking online I also see this option however it did not work for me:

- nvidia-xconfig --twinview
and restarting your X server.

There is a nice article on configuring twinview on the NVidia site: http://us.download.nvidia.com/XFree86/Linux-x86/1.0-9755/README/appendix-g.html