OK, I kept playing & finally got it to work with a variation of the solution in the technote: I left the CCSID of the file alone, changed the Stream File EOL option to *LF, deleted everything in the file & manually added a few lines:
I tried creating a file natively on the 400, as well as using a stripped down file as the result of a load convert -l, with the same results. Then I tried following the instructions in the technote you mentioned, using EDTF to create a new file, but the utility couldn’t interpret the results:
Mail Convert Failed: Unable to open database file: ‘/N% /IE!^~…’: File does not exist