Hi Dameon
In order to achieve your scenario, we can override the default Appointment Editor Template and add your required fields along with the default fields in the Appointment Editor template.
We have attached a sample for the same. In the attached sample we have provide custom field to customize the background of the appointment.
Note:
We have also planned to do some changes in Appointment editor and in binding logic in future release. Based on the changes you need to do necessary changes in Appointment editor template in above sample.
Please let us know if you have any concerns.
Regards,
Joy Oyiess Rex K
AppointmentEditor_c75828bf.zip