Dave,
If you remove the shrink wrap. there should be a mylar wrap around the front of the pack. I would cut a 1/2 moon in the mylar and then re-insulate with Kapton Tape. It is available from McMaster~Carr.
www.mcmaster.com#7648A33
Heat Resistant Kapton Tape W/Silicone Adhesive, 3/4" W, 36 Yards, .0025" Thk
In stock at $22.90 per Roll
I used this to insulate my F5D packs and it is really nice stuff. I still have the first (3) rolls I bought in 1998 and they still have some left. I used this method on my Baby Flight Streak packs and not only re-routed the wires, but shaved off significant weight too.
Archie Adamisin
Muncie, Indiana