Read reply # 4 in the thread you posted yesterday. It tells you how to do it with the G100 or a parallel port. Only the first sentance is about the gamepad. I have quoted it here for you. You will have to go to the thread to see the screen shots.
OK here is wht you do to set a button up as jog. In config, ports and pins, inputs, oem triggers, these are the pins you will use. Go to config, system hot keys and assign the button you wired the OEM codes you want. I have attached a few screen shots to help.
http://www.artsoftcontrols.com/forum/index.php?topic=4014.0Brett