Full day meeting in iCal export is something like this:

DTSTART:20131003T000000Z
DTEND:20131003T235900Z

In other words, from midnight of one day to midnight of next day.

Full day meetings created this way are not shown properly in other apps (Google Calendar, Evolution...)

Full day meeting created in Google Calendar or Evolution (and shown there in proper way) has iCal format like this:
DTSTART;VALUE=DATE:20131002
DTEND;VALUE=DATE:20131003

(and also set time transparency: TRANSP:TRANSPARENT)