You may be able to get to the actual circuit behind the buttons and disable the CAN part altogether. Chop the circuit and wire the buttons straight to the output via the same resistor pattern in the honda.
But just like reromero said, tinkering with the CAN system at all can immobilize the entire car and/or cause permanent damage.
Should have just not given up the honda :)
I have yet to test this, but I have a theory.
If you get the SWI-CAN adapter from PAC, you should be able to tap into your can-bus +/- wires and run those to the SWI-CAN. Then the SWI-CAN should output a usable signal that you can interface with the Fusion Brain. If you already have the FB then the PAC adapter is the only other thing you need to purchase. I haven't tried it yet because I don't want to fork over the dough for the FB and the PAC adapter just for steering wheel controls on my VW.
Bumping this for an answer to the above. ^
Or if you are interested in a can bus adapter, canusb is a device that hooks directly into the can bus. I have decoded the messages on the can bus that correspond to the steering wheel controls on my dodge charger.
I've even written a rr plugin that uses the steering wheel controls....
where can I get one of these and how much?(canusb)
the manufacturer's web site is http://www.canusb.com You have to go through one of their distributors. Last I heard, the distributor's website said the device was out of stock but that that was not up to date. When I bought mine, it was about $150. Expensive, but you can do some neat things with it....