Tone can you send me a picture of your battery set up?
Rather than sending a picture which would probably just confuse you, I'll describe it. After reading this, if you still need pictures, let me know. I'm glad to take them, but figure the description would help you out more.
OK, so remember my box is an m118. The functional difference between an m118 is that my box provides nominal 18V phantom power, whereas yours provides 48V. Since all of the Schoeps mics I own operate off of 12V phantom OR 48V, the m118 is a nice solution for me because it will run much longer than the M148. Other than that, it's my understanding that all of the sound characteristics of the two preamps are identical. For example, mine has the same two Jenson input transformers as those shown in your pictures.
I'm not completely sure of all the technical differences between my box and yours (since Oade covers the board with gunk), but the most fundamental technical difference is that it only needed six batteries instead of eight. They're the same batteries as you have...those 6V powersonics that have I think 0.5 watt-hour of capacity. However, when I reverse engineered the wiring scheme for my preamp, the wiring is alot more straightforward and logical that it is on your preamp.
So my batteries were arranged in two banks of three cells each. So that's two 18V batteries. Obviously each of these two batteries has a positive pole and a negative pole...four total poles...two blue wires and two red wires. The wires from those four poles are routed to distinct points in the circuit.
So when I removed the batteries from the box, all I did was to first snip the wires from the four battery poles (paying attention to which wires attached to which battery poles). Then I installed two sockets onto the external casing of the preamp box. I soldered the four wires to the two terminals on each of the sockets. One red wire and one blue wire to one of the sockets (corresponding to how the wires had been connected to the battery terminals) and the other red and blue wires to the other socket.
Then I built two cables to connect my external Naztech batteries to the two sockets that I installed on the case. Obviously, when I soldered the cable jacks, I paid attention to the polarity of the cable to the red and blue wires on the preamp socket to maintain a consistent polarity between the two external batteries and how the preamp was wired up when the two 18V internals were wired...making sure that the positive terminal on the externals supplied one of the positive/red wires soldered to the jack.
Now it doesn't matter anymore if the preamp switch is on or off because I simply unplug my batteries when the show is over anyway.
By the way, I used two standard size socket/jack sets from Ratshack. I can't remember whether I used 'n' or 'm', but whatever I used it's the same jack size as I already have on my Naztech batteries. The only reason I did this is so that the two cables I made are reversible.