Hmm, odd. Im sure I posted pics of the dual steeering setup, but I guess Im going cenial....
Its basically a metal bell crank set, with another servo/bellcrank thing used on the other side, where the 'slave' bell crank would normally go. This way the servos are connected to the bellcrank on both sides to double the steering power- simply use a Y-harness to connect the servos to the radio, and carefully centre both servos so that they dont fight eachother when at rest.