ouch, there is seriously no "easy" way on this then.

to the best of my knowledge, you cannot jsut magically create one;

each field, their meaning, data type and min/max values are all business dependent;

it might be if you have some code that either creates or reads the edi file iteself, you need to go through the code.

here's an example layout of one file the US gove happens to use; it goes to teh trouble to breakd own every value;

you need something similar to make heads or tails of the incoming data.

http://www.hud.gov/offices/cpd/systems/idis/edi/idis_edi_records_layout.pdf

Even an experienced code monkey like me would need something like that as a starting reference.