How to add timezone to Exif dates?

Hi,
I have been using exiftool, and so far its the most comprehensive
tool for the task.

I want to add the timezone to the EXIF header.
I travel across timezones and want to have all the times set to local
time. I want to do this in post processing.
I saw one post which mentioned the use of GPSTimeStamp to be set to
the UTC. So, I copy the DateTimeOriginal to GPSTimeStamp and want to
shift the GPSTimeStamp by 5hrs ( to represent UTC)

-the shift function += or -= works for DateTimeOriginal, but doesn't
work for GPSTimeStamp

Another way is to add the +hh:mm to the DateTimeOriginal. And I didn't
find a way in the exiftool documentation to show how to append a
TimeZone to the DateTimeOriginal (this method is not exactly acc. to
EXIF specs.)

Any help regarding this matter is helpful.

Thanks.

Hi,

Exif Pilot and Exif Pilot Pro allow you to edit the time field of
the EXIF data. You can try the programs:
http://www.colorpilot.com/exifpro.html
It will be very more appericated if you send the team your comments
about GPSTimeStamp editing in those software .