Hi,
DSpace defaults to using a UTC timezone for storing all dates in the database to allow it to be a global application. Since timezones may change (e.g. daylight saving time) at different times/dates around the world, we've standardized on using UTC dates in DSpace to avoid confusion around daylight saving time, etc.
Therefore, timezones are not currently configurable in DSpace. The code expects dates to be stored in UTC time in the database level at all times.
Tim