Matt,
Only rev.2.06 or higher can be updated directly from the website. Your Show Designer rev.2.0 would have to be sent in for an update.
You can also try using 32 dmx channels in the fixture library or use the Mighty Scan, which has the same amount of channels as the Dj Spot 250. You can then go to modify fixture and change the name to Dj Spot 250.