I've been playing the Japanese Emerald for a while now, and since there's so little information on how these events occurred in Japan by that time I decided to take a look at them on my own. I managed to find an absolutely amazing post on Pokémon Daisuki Club about the AuroraTicket Deoxys today. It's in Japanese, so I'm not sure if it'd help you or not, but I can share it if you want. Anyway, it's basically about a guy who was able to attend the distribution event back in 2004. Apparently, the method they used there doesn't actually differ from the one we know in America or in Europe. The player would need a Wireless Adapter plugged into the GBA to get the Pokémon and that's pretty much it. I'm not sure if there are any ROMs available on the internet to reproduce the Japanese event tho, which is very sad.