AEM: datepicker with timezone selector in a coral3 dialog

Is there any ready solution I could use to ask the user for a date + time + timezone in an AEM edit dialog? The Coral3 datepicker doesn't seem to support editing the timezone. I could provide an additional timezone select and have e.g. the datepicker save the date and time ignoring the browsers timezone with valueFormat="YYYY-MM-DD[T]HH:mm:00.000[Z]" , but that would mean I'd save the timezone and the date+time into two separate fields. Ideally I would have them joined into one. Any suggestions how to do that?