If you have a Wallet (perhaps on another wallet application) that is not created in MetaMask, but you want to register a LikeCoin ID with that wallet, you need to bind your wallet to MetaMask.
(If you haven't installed MetaMask yet, see this tutorial.)
The binding method is very simple, click the upper right corner of the MetaMask , then click Import Account.
Go to the wallet you want to bind and find the Private Key. Then paste it and click IMPORT.