I would just search until you find it. It'll probably be in the "brushless" section. Not to sound lazy, but I don't wanna search all night. :)
Basically:
- open the case
- GENTLY seperate the ESC from the case (there are thermal sticky pads)
- remove the heatspreader slab
- clean the FETs and case where the pads were
- cut a piece of 1/8" thick aluminum the same length and width of the old heatspreader (the old one is too thin to do the mod)
- use thermal epoxy (Arctic Alumina adhesive) to secure the heatspreader to the FETs
- let harden
- epoxy the ESC/heatspreader to the ESC
- let harden
- put the case back together.