date copy import timezones are incorrect for fullday events

Problem:

When importing a Google calendar ICAL file that has been stored in the local system using Date Copy, nodes are created for each event, and any events that specify the time have the correct time given. However every event that is a full day long has its start time offset back to GMT instead of my timezone (in this case GMT+7).

Steps to reproduce:

1. Install a fresh copy of Drupal 5 and all of the associated Date modules and dependencies (including CCK, Date, Calendar, Views), ensuring to use the latest versions (I did this test a week ago so...)

2. Configure a timezone on your site that is not GMT.

3. Create a new content type, add a date field with a required "end date". Set up your calendar view to display this content type, as given in the documentation. Make sure the field uses the site default timezone.

4. Download your Google calendar ICAL feed file and store it in a file directory on your server.

5. Use the Date Copy module and import the feed.

6. All of the events from the feed that have a start time and end time are properly imported, but all of the events which are full day will be offset by the timezone information (and will end up looking like they happen over 2 days in the calendar view).

Why is this happening?:

Looking into my basic.ics file produced by Google, I notice a difference in the DTSTART fields, depending on whether the event is full day or has a start time and end time defined.

For example (with defined start and end time):

DTSTART:20080912T001500Z
DTEND:20080912T014000Z

For example (with undefined start and end time):

DTSTART;VALUE=DATE:20080911
DTEND;VALUE=DATE:20080912

Fix:
Not sure, it's probably just a matter of checking for a defined start time more carefully, and if it doesn't exist, returning 0:00:00.

Hope this is enough information to resolve this.