I think you really do need analog at the very least, I have a ps3 pad for it but even then its tricky to get right settings so I use a cheap xbox 360 wheel.. a little bit of advice for people who cant afford Logitech steering wheels,do what I did and go to ebay and search for madcatz microcon steering wheel, I bought one for £38 with delivery, but I over paid as they go for around £15 / 20 euros (second hand) etc.. ok they don't have gear stick or clutch pedal but its much better than using a pad!
This here:
I know its not what you asked, but hope it helps anyway