Sounds like the BIOS real-time clock is being set by the kernel. That kernel function doesn't support local time zones, and will always use UTC.
If your distribution contains the file /proc/config.gz
(which is a virtual file containing the kernel configuration), the following command should return the relevant settings:
zcat /proc/config.gz | grep "_RTC.*HC"
Run that command in a terminal window and post the results.
Which distribution are you using?