The inputs to the holonomic.vi are: direction (0-360 degrees), magnitude (-1 to 1), and rotation (-1 to 1 - counter clockwise/clockwise). The x/y input from the joystick needs to be converted to degrees. There is a rectangular to polar coordinate conversion vi (re/im to polar) that can help. An example of using holonomic.vi is shown here:
http://www.chiefdelphi.com/forums/sh...63&postcount=1