Yes, you'd need to put some program in the middle (= mini-middleware 
) to modify the data, I believe. But in long term you might want to really consider using something more scalable for EDI.
Also I'm sure you'll run into this just few steps later - you might need to also maintain in VOE2 and VOE4 transactions, as well as material cross-reference in the customer materials info records (unless customer is sending your own material numbers, which would be a rare fortunate occasion).
Good luck!