I’m currently using an XBOX360 gamepad (arcade stick’s on the way), and it’s impossible for me to kara anything :(. I doubt I’ll ever be able to kara demon :(. Am I the only one, or is anyone else having issues with this as well?
Yeah, you’re gonna want to wait on the stick for that. You have to pretty much input the command for throw within just a few frames of f+mp. Ive been able to pull it off a few inconsistent times on the PS2 pad with thumb-rolling, but just for fun. For actual use, you’re going to have to get the stick. 
Some people claim to be able to kara successfully on a pad, but I’ve always imagined that to be one of the most difficult things to do on a pad as opposed to a stick. You might be able to do some creative buttons rearrangement, and hold your pad kind of like Tekken players do, but ultimately, I’d recommend getting a stick.
It really is damn near f’in impossible with a pad. I’ve been trying for years and not been very successful. (When we play we have one stick and one pad)
Pad players are crap. They can’t even kara throw consistently. How will they EVER be a threat for stick players 
Learn stick 
Is there a thread that has arcade stick techniques and tutorials?
Here is your whole tutorial. Practice. People have made tons of threads of tips on how to learn stick quickly, but it all amounts to nothing more than practice. There is no secret. You just have to play a lot. There is no special way to hold the stick, no matter what anyone tells you. Just play a lot, and you’ll get it.
Im a PS2 pad player, still wondering where to find a decent stick here in the US. Nonetheless i have my buttons arranged to my prefference, and i can do Kara-Throw in a secure constant way. Now Kara demon…thats a whole 'nother story.
I have a PS3 and the Virtua High Grade Stick is the best stick. It’s expenisive, but well worth it.