I don't think they can, but would be interested if it is possible or a way to send more tracks into the DAW at once.
I typically run another mixing board with the added lines, for example all the drum mics) into a stereo channel of the Model 12 and then into my DAW with the other channels. As long as you can get the mix from the external mixer right before sending and don't need to adjust the individual channels after recording, then it is a life saver for me to do a live recording with as many available inputs. I sometimes, when necessary run the drums out of Aux1 and into a stereo channel of the Model 12 and then another mic mix of instruments out Aux2 and into a 2nd stereo channel of the Model 12, so I can take full advantage of all my available inputs when needing more than just what the Model 12 offers.
Not saying that is the right, or best way, but it serves my purposes currently.