Finally saw ECS published the newest BIOS on their web site which has a released date on 22 Jan 2013 which is the one ECS confirmed working with Ivb processor. Not sure why it didn't got published until posting question here or rose a technical support ticket in their web site.
Link to the product page if anyone need to upgrade their BIOS: http://www.ecs.com.tw/ECSWebSite/Product/Product_Detail.aspx?DetailID=1201&CategoryID=1&MenuID=103&LanID=0
Thank you very much for your attention to the issue, ky_ecsusa
. I think we can give ECS a PLUS for addressing customer's issue and request especially during the busy Chinese Lunar New Year which is tomorrow 10 Feb 2013.
Happy New Year, everyone!