Might as well just post the info, keep in mind this is for an xbox360 controller and I'm using thumb-stick, but I'd assume it's roughly the same across the board for how d-pad inputs are read.
If you have that much of an issue with a different type of controller, bring up the stick configuration in xpadder, start #R, and see how low you need to go before you low block, that's where your horizontal size goes, and check your dead-zone for how much input it takes before an input displays on the screen.
For those who want to play on a pad that isn't supported:
1. Download Xpadder 5.3 or higher from somewhere, Google is your friend
2. Open xpadder and create a new controller, follow the instructions, and it should show your respective controller with all the buttons on the screen
3. Open your QKOJamma folder and open the keyboard configuration in notepad (download it from the GGXXAC Online website if you don't have it already)
4. Map the buttons from the keyboard config to xpadder by pressing on a button on the xpadder display. It will open up a keyboard and you simply click what key you want it to emulate with what button. If I remember correctly, on the emulator, Button 1 is Kick, 2 is Slash, 3 is H Slash, 4 is Punch, 5 is Dust, and 6 is an unregistered (?) button. The rest are self explanatory
5. Next, setup your appropriate directionals from the config onto the xpadder display's thumb-stick or d-pad, then click the wrench next to it. For me, the #R Dead-zone is 45% and the horizontal size is 32.
6. For macros, you are going to click on the button you want to set it to on the xpadder display, and click on advanced under the keyboard display. Here you will basically enter 3 of the keyboard keys into your cycle and insert a stop. This should press all 3 buttons at the same time, or at a delay if you wish, when you press that button.
7. Finally, make sure that you open up x-padder as administrator or it won't read your inputs from behind the game.
Let me know if anyone needs more help (Would probably be better to ask me on the reload IRC)