Hey Paolo, so after reading about the Elgato HD60, I think you're trying to kill a fly with a bazooka. The HD60 is a consumer product that connects to a person's laptop via USB 2.0 to record an H.264 stream at a maximum bitrate of 40mbps. Given those 4 points I believe it is safe to say the card captures a 4:2:0 signal in the 16-235 range. A USB 2.0 connection wouldn't be able to handle a 4:4:4 stream.
I'm not sure if Handbrake can do a 0-255 export, but you might want to try googling the x.264 parameters to see if it's possible. I would export a ProRes or Cineform file out of Vegas, compress that file in Handbrake at a CRF of 18-15 and then upload to YouTube.
@ericstrand11