Tim, Hi, we've not spoken before. I feel I must send you my congratulations. You've been paid a huge compliment by your company. What a priviledge to represent the company. I understand a little of how your feeling, but I am not aware of how much your difficulties effect you, but ANYONE would feel apprehensive facing such a trip. It's perfectly natural. It'll be a strange country, strange people, strange culture, strange as in 'different' and out of your comfort zone. Strange as in exciting, challenging and rewarding. Imagine the possibities of further opportunities to follow. Wow, you're on the up ! Seriously, take the above posters' advice, but remember if they didn't think you were up to it, would they risk sending you ? If you were'nt inteligent, and charismatic enough to take this massive P.R. opportunity, would they even consider you as a candidate ?
Not everyone is super confident socially. We can't all be the life and soul, super conversational, super outgoing, super ego building, people. Thank heavens for that.

Try hard to see this as the massive compliment that it is. Do some research on the culture etc. to build your confidence. Perhaps have 'practice' conversations with a trusted friend or family member. What to say, how to r e l a x and eventually, actually e n j o y socialising. Lots of people worry how they come across socially, nothing wrong in asking for a few pointers. Remember too, other people that are meeting you, will be too busy worrying about their social graces, to notice yours.
As long as you don't dance naked with a rose between your butt cheeks, you'll be fine. That doesn't sound likely.
No one is expecting you to get a personality change, and suddenly become Mr. Super-social-bags -of -confidence. You obviously have the requirements for this trip, so grab the opportunity, it's a massive compliment to YOU.

Practice in private as I've suggested, maybe write some short presentations if that would help. Basically just prepare a little before the trip, then r e l a x, it's going to be f u n. You probably will be spoilt rotten, lucky man !
Don't forget some personal relaxing music, and your headphones. Calming music is wonderful. Practice S l o w , c a l m breathing.
Don't forget to smile too, no one rejects a smile.

Please try to enjoy this trip, and come back with tales of your adventures for us to hear.

When you're
feeling anxious, read our posts, over and over, and try, try to believe in yourself, your company obviously does !

Take care and e n j o y !