This is not precisely what you're looking for, but... Peripheral Electronics makes a line of adapter from lots of manufacturers steering wheel buttons to IR. I've never used them, but I did run across the website: http://www.peripheralelectronics.com Let me know how it turns out, if you come up with a solution, I'd seriously consider retrofitting the buttons to my M Coupe.

-Zandr
Mk.I #0150 10GB
RioCar #010101243 10GB (96GB here I come...)
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-Zandr
Mk.IIa #010101243 currently getting a 500GB SSD. More spares in the shed.