According to ESi, the vehicle speed sensor was only fitted to manual transmission vehicles and three speed auto's. I imagine other models may use an ABS sensor ? I don't know what you would do if it's one of those, maybe a converter ??
Anyway, the VSS is positioned above the selector lever position switch, on the auto transmission unit. The signal wire is pin 3 and you should see a square wave, approx 8v depending on road speed. This links into the transmission control unit at pin 58 & the engine control unit at pin 66. On earlier models it looks like the VSS talks direct to transmission ( don't know what pin ), then transmission sends it on to engine ECU ( still on pins 58 & 66 though ).