Hello Tech_Wiz (and others):
I also have a mobo with USB 2.0 headers, and would like to install USB 3.0 connectors on the front panel. The same as you, I am seeking an adapter to connect USB 2.0 mobo headers to USB 3.0 20-pin.
Did the Lian cable below work for you?
Thanks,
cerkit [B]reaker