Easy peasy, i done it
Just buy a complete rs2k disc beam and Cable. Four bolts later and you will be job jobbed
SIMPLES
And you will have a Handbrake that works
Heres mine when i done it



While you are at it why dont you do the fronts to match and fit some 285mm discs and proper sized Calipers from either an Escort Cosworth or Mondeo v6.
I went down the Mondeo route cos they were in stock

Totaly transforms the car