Yeah I'm having AS exam now. Yeah I appealed before, but as far as I remember, I wrote a letter to the Pengarah JPA, that's all. I don't think you need to go to Putrajaya if you couldn't, just send by postage is enough. Chance of success? Depends on your result and them actually. I don't know.
anyway... all the best..... this year is kinda different .... i knew that a chinese with 5 A+ and 5 A and 1 A- and 1 b got to JPA germany..... so i don't really know how they judge.... they have their own system though