Even on a Linux box, you can usually see that the device exists without permission to use it.
The CP2012 works fine in recent OSX releases, and does not require any special permissions. However the proper driver from SiLabs must be installed - it is not included with OSX in the way that an open source driver supporting that converter typically ships with most Linux distros today.
Any ideas as to why I can't see the Omega when I scan /dev/tty? I've tried installing the driver many times and it hasn't given me any error messages.
See if it is listed in the USB section under system report.
Try a different cable. Try it with a hub. Try it without a hub.