Check out the comments here... seems they are not quite there yet:
http://www.3cx.com/blog/releases/3cx-phone-system-12-alpha/#comments
On windows 8 - my config files were empty for some reason when I saved them. It was strange... when I saved ona win7 machine then opened from the win8 machine the config file had info...
When I manually added an account on the soft phone it worked.
But CTI mode was not working.