I believe this works:
Once you have completed dictation and made the charge, you can then select "pull superbills" with a right click with the patient name selected. At the bottom of their account page for that DOS, you can enter their "co-pay". Then save. It should show up correctly on the CMS 1500 form after that. I've only tested this once with my "test patient" but it seemed to work.
Carla Gibson