Whole day timestamps invalid in ical export

Whole day calendar items break the ical export, because the DTSTART and DTEND fields are then invalid. This is what a two-day event for February 5-6 generates into the ical export:

DTSTART:20110204Z
DTEND:20110205Z

This is what the export should have:

DTSTART;VALUE=DATE:20110205
DTEND;VALUE=DATE:20110206

Also note the one day difference in the dates. This is probably due to the local timezone being ahead of UTC and the DTSTART/END values just had the time-of-day part chopped off from a UTC timestamp, instead of being properly converted from timestamps to dates.