Julie,
Given using the same variant/message for both in and out the BULKCOPY should work as you think.
So that means there is something wrong with the offending message.
You are sure you are not getting any mis-matched IR tags or other error messages?
Have you tried extracting that offending message into its own file and just running that one message through the tester (should get the same result but you never know).
Have you tried sending the offending message through the Xlate within a running engine (in test of course)?
Sorry I am not more help but I don’t use BULKCOPY very much.
Jim Kosloskey
email: jim.kosloskey@jim-kosloskey.com 30+ years Cloverleaf, 60 years IT – old fart.