fly by wire throttle

When converting to fly by wire throttle as part of a 20v conversion using factory engine management do you need to use the complete fly by wire throttle pedal assembly from a 20v car or can you use a modified mk1 pedal to operate a seperate fly by wire unit such as used on mk3 golf tdi, image below courtesy of this thread http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&p=693112