Unfortunately, there's only one thing you can do; buy a better adapter. A co-worker bought the Kiki-Joy adapter, but because it can't interpret arrow steps as buttons, you can't do left-and-right and up-and-down presses and have it work properly.
The only thing you might want to try (and I'm not saying this is a good idea, but it worked for my friend until he got a better adapter), is to turn the mat so that it's a diamond, not a square, and map the buttons which are on the mat's corners (X, circle, square, and triangle) to up, down, left and right. It makes you step 40% further for each step, but it can work...
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Left-Left-Right-Up-Down-Thud-Ouch!