The move has a 12-byte data structure. The order is: 1. effect, 2. base power, 3. type, 4. accuracy, 5. pp, 6. effect accuracy, 7. target that the move will affect, 8. priority, 9. unknown byte, 10,11 and 12 are padding.
Just go to a hex editor, search the location of the move you want to edit...