I wanted to post here quickly as I've gone through a round of emails with Martin many months ago to no avail. We could not figure out why the AT&T version would not work with this software on my phone with the stock AT&T Jellybean 4.3 ROM. The conclusions lead to the hypothesis that it was the built in Knox security and/or a carrier version problem.
A complication was that I had already encrypted my phone, and was not in the position to start over to get rSAP working. So I've waited until last week when I decided to bite the bullet and upgrade fully to Kit Kat 4.4.2. I began anew wiping the phone completely. (after backup of course)
Another complication is that I'm not sure if this will work with the stock AT&T Kit Kat 4.4.2 rom as I've already proceeded to root and overwrite with the Dynamic Kat 6.1 Rom, which by nature removes all Samsung Knox security, etc. I am using Safestrap 3.75 to boot to this Rom version in the stock slot position.
Having done this and installing Bluetooth Sim Access and Bluetooth Sim Access Installer, everything is now working perfectly. I am running a Volkswagen 9WZ bluetooth module in my car and now have full SMS and external antenna functioning.
just wanted to share in the event someone else is trying this and running into brick walls.