Originally Posted by SIN REKA
Do you have any music on your hard drive? If not , put a song or two on it and go back to Tekken tunes. Pick a stage, switch to your original music library and choose a song for that stage.
As for the "Tekken Black Belt" achievement, I achieved 1st dan, but didnt get the achievement. It did unlock after I had won a match while as a 1st dan. I'm guessing that it will also unlock if you win your 1st kyu to 1st dan promotion match (can anybody confirm this?).
So that's how it works? Let me try it out...
Update: It works! The thing is, after doing what you told me to do, it's important to make sure to exit out of the mode completely. Once I did that, the achievement unlocked. Thank you!