Just created an enhancement request to make ED40 readable to other issue methods.
At Inforum they mentioned they were having difficulty coming up with a solution that would fit everyone and it occurred to me that we have already all figured out a way to map the PO header to an account for EDI. If instead of TPID_O the POs issued to Paper/Fax/Email looked for PO_O records we would be fine.
At any rate, I'm going to see if I can bribe my IT to at least put it on the wish list for IPAs. :)