What standards are you using? ANSI X12? Using a VPN is the best route but can be costly. With the VPN you can get templates, at a cost, for the different types of documents. Parsing the data is easy enough once you know what the document is.

Who are your trading partners and what are their requirements? The worst part is that they all use their own rules and you have to code for every exception.

Sterling Commerce has been around for some time. GE is another.

If you are going to develop the means of comunicating between partners then it becomes real work.

I hope this helps…