Hey Wes,
be careful on the type of foam you use, some types can melt when close to high heat (is that a 12 or a 6volt v-3?). I would go with pipe insulation, the type a plummer would use. I'm now using this on my cables going to/from my v-3 and DAT, in my Rakgear bag (laptop sits on the top of the bag), and it works great. I would also adjust a slot for the cable to come out on the side of the insulation.
Peace,
~Russell