We're working on an interface with Construction and a program called e-builder. It's basically taking the requisition process for new construction projects and handling approval routing.
So when it sends to Lawson, the thought is that it will send a PO520 and create POs.
The wrinkle is change order - is anyone accepting automated changes to existing POs? Will PO520 do that? We're looking at PO520 but are open to any suggestions
Since you are receiving requisitions. Isn't it better to use RQ100?
As long as PO01 has numeric POs are auto numbering it should be able to add POs using option 1. Make sure you have a number defined on PO01.
If I remember correctly the problem was you had to add the header before the lines (as in run a file with all the headers and a separate file with lines - don't remember). Play with PO53.1 and PO53.2 to get the process down and then you can replicate using PO520.
If you go the PO20 route I would still recommend using PO53 for a little more control.