If a coin is not listed on your selected data provider (CoinChoose.com or CoinWarz.com), you can it manually in the Coin Manager window. Go to the Settings tab and click Other Tools... button at the bottom. In the popup menu, select Manage Coins. You can also change your data provider in this window, but keep in mind that using CoinWarz requires an API key, which may cost money depending on how many API calls you use.