Motu 8Pre and Sonar 7PE available driver or track assignment

  As stated earlier I have Sonar 7PE and a Motu 8Pre. I set up six stereo Audio tracks in Sonar and I need to assign the inputs to the Motu. I may not be explaining this properly, as this is new to me. So, in each Audio track there is an input/output. I set the input to a Motu track/input/driver assignment. Sorry I am not in front of it and do not remember exactly what the terminology is. My problem is that I would think that in the Audio option/Driver Tab that I would have Eight inputs listed from the Motu, as it has eight inputs/preamps, but there is not that many...I think 3 & 4 are missing. What I get are 1-2 with a left and right or stereo choice. But I don't get all eight inputs. Should I change the Audio tracks to mono, as I can still pan with it I think. And is there a global setting that i missed to get all eight inputs/preamps to be available. I guess I just think that I should see Audio Track 1 going to input 1 of the Motu and so on until I use all eight preamps. Thanks for your help. Also, I can't change my buffer size to avoid drop outs. It is not available on my Audio panel dialogue box, so do I select the Asio panel button, which brings up the settings for the Motu interface and select a higher number value in the "samples per buffer" box and what about the "sample rate" which Motu says is a Global sample rate...thanks again.

Thanks Greg!