To connect X-Plane to SPAD.neXt some housekeeping has to be done first:
Start SPAD.neXt and head to Settings->Application->Simulations
and enable the X-Plane Support.
Now click on the "Configure"-button next to it.
A dialog will open and tell you if the X-Plane plugin for SPAD.neXt has been detected already, and if it is the correct version.
If it's not, click in the "Install SPAD.neXt X-Plane plugin" and the plugin installer will launch.
if SPAD.neXt and X-Plane are running on the same computer, you are done now. Launch X-Plane and have fun!
Remote Connection
If SPAD.next and X-Plane are running on different computers, you will have to tell the plugin where SPAD.neXt is running.
First start X-Plane one, and exit it again.
Now head to your X-Plane installation folder and navigate to Output\Preferences
Here you will find a file called "SPADneXtConnector.sdm". Open it in your favorite text editor (e.g. notepad)
The file will look like this:
{ "LocalConnection": true, "ServerHost": "127.0.0.1", "ServerPort": 8181}
change the "true" to "false" and replace "127.0.0.1" by the ip (IPv4 or IPv6) of your SPAD.neXt-PC.
The port should be ok, however if the port 8181 on your SPAD.neXt-PC is not available SPAD.neXt will select another one. To find out which one, head to Settings->Application->Expert in SPAD.neXt. You will find an option "Remote Services" there and the Port that is being used.
Save the file, and make sure the firewall on the SPAD.neXt-PC has port 8181 open.