Although, buying a Japanese Xbox 360 so you could get it with beta FFXI is a very "cool mom" thing to do, it is also a very dumb thing to do, unless you or your son actually knows Japanese. For one, although there are a lot of region free games, most probably won't be, which means if you see a game that comes out in US that is region locked that you want, you won't be able to play it on your Japanese X360, so you will be forced to import a Japanese version if there even is one(which will likely have Japanese text as well), you will probably run into this problem alot. As for not getting any help from support lines, that does not come as a shock, considering you are trying to play a Japanese game, when you don't even know Japanese. Not to mention the fact that it is a beta version for FFXI which is completely pointless to have, quite frankly. Also, I've read some impressions of that beta FFXI
HERE, and it appears to be nothing special. If I were you, I would sell that X360 & FFXI as soon as possible so you can get as much money as possible for it, and then buy yourself a US X360 and just wait for a retail FFXI to come out here.