Groupwise may do this different to exchange, but we seem to have a problem with putting in appointments in different timezones

If I enter an appointment in Groupwise (Posted or sent to myself) and I set the timezone for a different area, the timezone appears to be ignored.

Set Calendar with two timezones. Sydney and Brisbane Australia. They are an hour out.
New Posted appointment set for 11:00am Sydney time, it should appear in my calendar as 10:00am. I enter 11:00am and set the timezone in the item to Sydney
However, it shows as 11:00am Brisbane time and 12:00 noon Sydney time.
I go back in and edit the posted appointment and it now shows 11:00am Brisbane Time.

Do the same thing in Outlook 2007 (What we have just migrated from) and the appoint gets registered as 10:00 in my calendar.

I think this is a bug!

Am I missing something, or do I log a call with support?