Afraid I cannot help on how to immobilise the airbag circuit to work on it but maybe try to pick the brains of the local mechanics as I doubt the system will be different to most if not all makes of cars.
An update on my light is that last Friday the guy that did the cambelt and water pump plugged his Snap on diagnostic tool into the car but this time told it that it was a 3.0l Camry and it connected.
The fault came up as passenger airbag so he cleared the fault as he considered it to be an old fault that came back when the power went off a sort of ghost fault.
So far so good as the light has not come back on and he re scanned it and it shows no fault present.
Obviously this would not be any good if it was an engine fault unless they use the same software but I would say the Camry is probably two cylinders short of a proper engine lol, correct me if I am wrong.