Hi mate,
I've tried to reprogram both new keys but with no luck. it seems that only one of them I managed to make it work on my car but lock and unlock functions doesn't work. i can only start the car with the new one. With the other one, I couldn't do anything, however the key has a panic button on it. So, to sum up my learnings, if the key is from UK, and has the open boot button than it should work, if not, then it will not work on the Au ECU's.
Another thing though, I've had a chat with a nice chap from an car alarm company from Brisbane and he tod me that if he installs an alarm on my IS200 he could reprogramm and sincronyze the key in order to respond to lock, unlock, panic and so forth. So having said that, I think I will give this a go. Is going to cost me $300 but at least I will have an alarm and some additional stuff that comes with.
If you have any other ways it would be great if you could share it with us.
Cheers