Having set up 3 different low cost stabilization systems so far one thing I have learned is you are pretty much on your own. The radio manufacturers disavow knowledge because they didn't make it. The sellers disavow knowledge because they provided you the manual to read. The newsgroups are quiet for the most part probably because of the litigious nature of the average person. The original manufacturer is hard to find because they are often Chinese and the products is relabeled. The documentation is confusing, at best. One solution is to use a not so low cost one like Eagle Tree (which I also tried one) but even that doesn't always provide the answers. The best advise I have, which is too late for you but not for others thinking about it, it to read as much about the unit you are looking at BEFORE you buy. In some cases there are online support groups that actually can help - once you find the right person to talk to. Download the interface software just to get a feel for how it works. If you have to be an expert computer operator/programmer just to run the interface software you have got the wrong unit.
Also, just my opinion but while a serial interface into the unit is nice setting up the protocol between the unit and your radio can be a nightmare. Is it SBUS, IBUS, some proprietary SBUS type they call SBUS, or something else entirely? That is likely the problem you have.