The AI personalities from AoM aren't available under the XPack. They absolutely don't understand the Atlantean units and many of the game changes.
The XML file setup is still the same, so you can create new ones if you want. To make a new AI, create a copy of one of the loader files, and refer to that in your XML file.
You'll see some control variables (starting with a "cv" prefix) that can be changed in the loader file to make them behave differently. All the cv variables have a valid range from -1.0 to +1.0. For more info, look at the file named aomxaicv.xs.