haha, sry my english is very bad..
You buy one item in website shop, and go in-game to npc, say hi, check, and he say, you have XXX and XXX items to withdraw ..... or if you don't buy anything he say, sorry, you don't buy anything in virtual shop, if player buy, he say, you want withdraw XXXXXXX now ??, player say yes, and player get item =)
or same.