Anybody from Asia?

hi, i'm wondering if anybody had(or currently) worked in Asia (Hong Kong, Korea, Japan). My particular interest is with Korea (Seoul) office, because there might be an opportunity in near future. (It's a BB bank IBD)

I went to top 10 undergrad finance school in East Coast, and currently doing market risk at BB bank. However my interest is with IBD, and with markets like these days and with my current experience, it seems almost impossible to make a transition to IBD.

Therefore, I decided to shop in Asia (Seoul regional office), and my concerns are below:

1) some say it'll be very difficult for me to return to states with similar job function, since the experience will be focused in Asia. (i kinda doubt this, but then i don't know any better)

2) double tax? anybody know this? (i'm u.s. citizen, and wondering if i have to pay taxes in two countries: US and Korea)

3) would asia experience apply towards US experience metrics? meaning if I spend 2 years in korea, would US banks consider me as 3rd yr analyst or 1st year associate on my return? or would they reduce a year of my experience?

Any inputs will be appreciated for it is rather a serious concern for me since it requires me to move from NYC to Seoul, take care of recently purchased condo, car, etc. :(

Thanks!