Fully Kiosk Browser service set_config and sleepSchedule key

i opened an issue on GH about the FKB integration, and its set_config service. when FKB wasn’t an official integration, you could use the set_config service to set several config parameters, including the sleepSchedule key; in the official integration, i can’t do it anymore; the sleepschedule value must be in JSON format, but the service only accepts a string. has anyone already encountered this problem, or perhaps they have a solution?

- variables:
    heure_coucher: "{{ ( as_timestamp(states('input_datetime.heure_coucher')) + ( 0.5 * 60 * 60 ) ) | timestamp_custom('%H:%M') }}"
    heure_reveil: "{{ ( as_timestamp(states('input_datetime.heure_reveil')) - ( 0.5 * 60 * 60 ) ) | timestamp_custom('%H:%M') }}"
- service: fully_kiosk.set_config
  target:
    device_id: xxxxxxxxxxxx
      data:
        value: "{{ [\n  {\n    \"sleepTime\": heure_coucher,\n    \"wakeupTime\": heure_reveil,\n    \"dayOfWeek\": 9\n  }\n] }}"
        key: "sleepSchedule"

@cgarwood do you have an idea ?