So the supplied TTi driver won't do the job then, so what you are trying to do is access the firmware that you're not supposed to have access to is that it? TTi won't give you the software to enable this either in case you end bricking the TTi box or try to get it to do more then it was designed to do and then maybe claim it was faulty or something from them? Sorry if it seems obvious to you but to a non programmer like myself, it leaves me scratching my head.
Aim-TTi, like so many others, seem to believe that the world only consists of Windows. So if you're going to use any of their kit on any other platform you're on your own. They have no drivers available, except for Windows drivers, for any of their products.
The driver setup on OS X is much easier to work with than Windows, oftentimes you can get something generic and widely used like the FTDI serial drivers (in thousands of products) to work just by changing a configuration file. Problem is that nowadays those configuration files come with digital signatures to protect them from malware, and working around that is a non-trivial exercise if you want to keep the system integrity protections in place one you're finished fiddling. You can explicitly turn them all off, but that kind of defeats the purpose of having them there in the first place. Selectively saying, 'yeah, I know that driver is unsigned, but I say it's OK' is difficult for drivers (but easy for unsigned applications). The protection is an improvement, but it makes some of the quick fixes of the past into a rather more time consuming exercise.