i actually got the sound working now, but i got back to square one, with no 'mode' dropdown present
but, 'profile' is now present, and still, only 'analog stereo output'
until i realized that my laptop doesn't seem to support 5.1 output at all
http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=27&Level=5&Conn=4&ProdID=166
well, it seems that i have to search for 5.1 usb audio card.
thanks for the help.