SQL Server time is based on the system time kept by the bios of the server. To make it appear as though it is in a different timezone, you will need to create a function or do some datemath when you select insert and update any dates.
I'll probably blur it out again too soon, but I don't think you can make SQL Server return anything other than the data/time of the OS it runs on (regardless of whether it is a stand-alone server of a DC) when doing SELECT GETDATE() or SELECT CURRENT_TIMESTAMP. Information on all system-related resources is available to SQL Server ONLY through registry entries and/or Windows API calls. In the case of date/time you won't see anything different unless you manage to alter the corresponding DLL.