Hi Ricardo
Thank you for your update.
In DateTimePickerAdv control, MonthCalendarAdv has been used as a Sub Item of DateTimePickerAdv and requested Today / None Buttons are Sub Controls of MonthCalendarAdv. So this Designer customization will not be serialized for this level from parent and in this case. customization needs to be done through Codes. Please let us know if you need any further assistance.
Regards
Kannan