Might not be bad to use a third party to hold and send goods...ie, you and your trader send to me, when both parties have sent all goods, i send each their respective goods..maybe for a small transaction fee?
Then you both parties would have to trust the 3rd party person... a general trade system would be best... maybe where you can post your items for trade for a certain price or items and people can click to trade... or pm trade details and then start a trade