have a peek here:
http://www1.bbiq.jp/ikinari/xmods/index.html
the pictures are explanation enough really. all you do is remove the brown and orange wires from the servo pot and add a 4.7 – 10k resistor to each one and resolder. the attached pic is my modded servo. you can use much smaller resistors than these, down to 1/8 of a watt:8ball:
