AES-NI (AES New Instructions) from SandyBridge CPUs are not forwarded to Guest

[USBProb]

Problem is there ​http://forums.virtualbox.org/viewtopic.php?f=7&t=42951 documentated. Host (Intel i5 2500K) shows in CPU-Z AES support, in Guest there is now AES-NI support. I think that can be solved with a (V-BOX)BIOS-Update, had a notebook with the same problem, BIOS update and then AES-NI worked. Perphaps these links help ​http://communities.intel.com/thread/23583 and ​http://forum.notebookreview.com/windows-os-software/582628-aes-ni-support-truecrypt-sandy-bridge-problem.html