To create record with proteus, you must instantiate it, fill the fields and call save. E.g:
sale = Sale()
sale.party = party
line = sale.lines.new()
line.product = product
line.quantity = 1
sale.save()
To execute buttons, you can just use the click method with the name of the button.
If you want to see more example of proteus, you can look at any scenario (.rst files) in the tests folder of any module.
About EDI, we have already some Electronic document implemented. But I’m pretty sure the community will be happy to support more format.
It may also be useful to take a look on how we implemented the CAMT054 parser.