ive tested the cooling idea before on a old pack and a new-ish pack. the matcher told me not to cool while charging but i was still curious so i did it once just to see the results.
anyway, yes, i got more mah into the old pack (alot more) put the punch was not better, so i don't see a point.
i tryed cooling my pack whilst step charging it during summer. what i did was similar to Jef Brown's idea. i cooled it for steps 1, 2 and 3 of the step charge, but took it off the fan during the 4th step. i got more Mah's and the pack peaked at a reaosnable temp (roughly 45 degrees celcius to 48). a pack step charged without the fan for the entire charge reached about 51, maybe a touch more. (this was hot day).
i only did it once and stuck to what the matcher here in oz told me.
also on a hot day i tryed also placing a fan far away from the pack, basically so it is like a very small breeze passing through the pack just to stop the heat from building up around it...i don't think it did anything, and again, i only tryed it once.
usually if it is very hot, i don't bother racing anyway. it kills the motor, and it fries your brain being in the sun.