Trouble getting signal from Vmixer 480 to Sonar X2 Essentials

Hey guys i have a bit of trouble getting my computer to receive signal from my computer, through the Ethernet REAC. The computer can tell that the V MIXER has been plugged in. I automatically assume the computer is picking up the 40 left right and stereo channells all you have to do is assign the imput to the individual channel. Is that correct?
Do the channel numbers in the imput section on SONOR correlate with the desk channel numbers?
I am only new with this equipment any help would be considered great.