Examples for data acquisition are in the LabVIEW >> Examples >> Daq >> anlogin >> anlogin.llb directory. You will still have to do the following to programmatically set the measurement mode to differential.
You can set your data acquisition with the AI Config.vi in LabVIEW. There is an input for "coupling and input config". A good trick to make sure that you create the cluster correctly is to use your mouse as the wiring tool and right-click over that input. Then, choose Create Control or Create Constant. The cluster will pop up, and you can use your operating tool to choose differential mode for the second pull-down ring in the cluster.