The memo is optional and has nothing to do with your account. Bter allows withdrawal to either (1) a registered account name or (2) a public key of an unregistered account from your client. If you leave your public key here I can send you some PTS to get you started.
For clarification: when you launch your client you will be asked to enter an account name. This account will remain 'unregistered' until you fund the account and click the option to register the account. If you want to send money to this 'unregistered' account, you need to do the following:
1) Click 'My Accounts' in the left menu bar
2) Click the name of an existing account on this page (or click "Create New Account" to create a new one)
3) On the next page, under your account name, you will see an 'Account Key' which is a long hash address starting with the letters 'PTS...'. This is your account's public key. You can fund your account by sending PTS to this account key.
Let me know if you have any other questions.