In the BandHelper general settings you can set the week start day to Monday and this is reflected in the calendar views of the various devices and also in the web interface. If you use the web interface to generate a new event and set the start or end date there is a calendar widget that pops up to simplify the date entry for you. This widget always shows Sunday as the first day of the week, regardless of your general settings. I already have entered wrong dates a few times, because a quick glance convinced me the "S" on the end of a row of days must obviously be a Sunday.
I think this widget should reflect the 'week start day' setting, like the calendar view already does.