Here:
Found some pics of my setup.
However, I don't have the gun anymore... so you will have to go with theses...
You have to cut the part in blue, then the wires will clear on left and under the mechbox.
As for the adapter, you can have the wire inside OR outside the tube, as buffer tubes made for stock batteries have a place to fit the wires, that way it is not squeezed by the washer of the mounting bolt.