Colin,
Hang in there. The one bad thing is that they never run out of beans. The other bad thing is their music stinks... The good thing is we are out of range. There are some really good bean counters but they usually don't work with EDI.
There are ANSI X12 standards and if you could get your hands on the standards for the documents you are working with you can design around that and then add the (never eding) exceptions as you get them.
Good Luck
John N Ranauro
Cellent Systems
Independent Consultant/Software & Database Developer
john@ranauro.com