Here's how to connect to a remote QSC Q-Sys Core via Domotz. These directions and the attached script are based off the Extron from remote thread. I've modified the script to work with the ports Q-Sys uses.
1. Select the Q-Sys Core from the Domotz WebApp → Device list → Device
2. Go to "Connect" tab
3. Click on "Open a TCP tunnel"
4. Insert the TCP Port. By default you will need to open 3 tunnels for the following ports: 80, 1700 and 6504.
5. Wait to have the tunnel setup
6. Repeat steps 3 and 4 for each port.
7. You will have a host and a port for each TCP Tunnel (see the Extron thread linked at the top for screenshots).
8. Open the .bat file as Administrator (see link below) and enter the requested information on the screen.
9. Add a hard link within Q-Sys Designer following QSC's documentation and use the loopback address you chose (e.g. 127.0.0.100). Note: Make sure the mode is set to HTTP. You should see it turn green.
10. Click OK, then File -> Load from Core & Connect and you should see the Core listed there to connect to.
Domotz Q-Sys Connect.bat