I wouldn't have thought you would need an extension tube with a reflector - i didn't need one when I used my QHY5 (which is very similar to a Starshoot autoguider) in my newt. However if you need one:
http://www.bintel.com.au/Accessories...7/catmenu.aspx
I'd be looking at the settings on the camera first, and confirm that the camera is communicating properly with your computer. If you shine a torch at the sensor of the Starshoot, it should show up on the display on the pc screen.