I will be visiting Seoul for 2 weeks in August for business purposes (although will do a spot of sightseeing at the weekend). My employer in their infinate wisdom give me a company credit card for my expenses but do not allow any type of cash advance. Therefore if I spend cash I must convert my own funds ahead of time, get receipts for absolutely everything, and then exchange back what I do not use. They will cover exchange fees but are not forthcoming with what happens with exchange rate fluctuations and unconvertable denominations (e.g. coins).

I therefore want to find out the extent to which it is possible to keep to credit card and avoid cash spending while in Seoul (I have never visited Korea before).

Places I will likely spend money:

Food - both restaurants but also food courts/fast food (possibly)
Taxis
Metro system
Limo bus to/from airport

Can anyone shed any light on whether there it's possible to use a card for any of the above? (I understand metro vending machines take cash, but is there anywhere at all that will accept a credit card to buy/top-up a T-money card?)

Also how likely is it that I can get a receipt for every cash expense?

Thanks in advance.

P.S. Nothing to do with this. Will my US (AT&T) iPhone work in Korea? Billed directly to work, and given their inflexibility on helping me out regarding the above I'm not hugely interested in the cost - just whether it will work or not.