"This apple ID has not yet been used with the app store."

Hello. I've created an Apple ID accout on the apple.com website so I can use the app store to update or download apps. However, when I tried to do that, the app store displayed a message saying, "This apple ID has not yet been used with the app store." To quote http://support.apple.com/kb/HT2589, "If you already have an Apple ID, you can easily use it at the iTunes Store or Mac App Store. You already have an Apple ID if you bought something at the Apple Store, registered your product online, or used the My Apple ID page." I am very confused, because I know for sure that I have bought a MacBook Pro (10.8.4) in Hong Kong some weeks ago. Here is a procedure of my attempt to get XCode:

1. I wish to get XCode

2. I enter my Apple ID and password just as I do to log in to apple.com

3. ???

So what is the meaning behind this? Do I restart my computer? Is it because I bought my MacBook Pro in Hong Kong that I must register an Apple ID in the Hong Kong Apple website (which, in my personal opinion, is a bit absurd)? What do I do? Please help.

Many thanks.