Make a hong kong master account (18 or over) with a real email address on your PS3. (Don't use the same email as your main account)
Make a new hong kong account (under 18) and it'll ask you to enter the email and password of the master account and it'll then send a confirmation email.
(On your PC) Follow the instructions in the email and make everything up (names/email etc), just make sure that you select no restrictions for chat and spending at the end (very important).
Now that's confirmed, go back to your ps3 and sign up as an existing user with the details you just made up on your sub-account sign up webage.