Along with the flexi-hose running to your caliper from the master cyllinder, there should also be an electrical cable/pigtail running into the two front hubs as well.
The rear ABS is taken from the top of the pumpkin on the rear axle.
Check these pic's of a hub for sale on e-bay.com :- Item number: 120361560602

Al.

 

the stupid part is the rear abs only works with the gears, not the indiviual wheels