Previous versions of mac os lack support needed for composite devices (the native port exposes a composite device: serial + hid). If you only need a serial port you might create and upload a sketch that is a serial port only. I had that running on the leonardo. It probably can be made working on the due too. See here: Leonardo doesn't talk to serial monitor in windows 7 - #8 by PeterVH - IDE 1.x - Arduino Forum
thanks for your reply. but it seems, that it is not a os problem.
i tryed to get a serial connection on mac osx 10.8.2, arduino 1.5.2.
with the same result.
i can upload a sketch successfully, but i can not get a serial connection with the the "serial monitor" app (or other applications, which can send/receive serial data)
perhaps it has something to do with the fact, that it is a "TAIJIUINO Due Pro" board.
It is not the serial port that would force the upgrade, it is the composite device.
Downloading a "serial port only" sketch, will work for mac 10.6.8 too.
I just tried the approach I posted before, and can confirm it works on the Due.
(tested on linux, due native port enumerates as serial port only and ASCIITable sample works (when using SerialUSB instead of Serial, I missed that on your first post))