What about an external plugin? Something like the ASI Loader script, "GInput" for the GTA classic trilogy?
The advantages for this, is it wouldn't touch the keyboard mappings (allowing a simultaneous input between gamepad and keyboard+mouse), and the triggers (Z-axis + and -) would respond simultaneously letting me brake while throttling (a problem from DirectInput), apart from covering the rest of features from the console support, like vibration (and not just for 360's, but maybe even for DS3).
Please, man. If not in this patch, at least on another mod you or maybe someone else create, inspired by the mentioned script.
Anyway, thanks for your help