You need to plumb it into the rear brake circuit. This is easy in a rally car as the rear circuit is seperate to the front and the pipes run through the cabin. On some road cars, and without checking I don't know about the clios, the circuits are split into 2, with 1 front and 1 rear brake on each. This obviously makes it trickier.
With regards to road legality etc, you must leave the cables in aswel. This is an MOT requirement as the parking brake must be a seperate system to the foot brake for emergencies, nothing to do with pressure going down as far as I know. Even auto handbrakes use a seperate system, usually not hydraulic.
Also, the handbrake must have a ratchet mechanism fitted to prevent it releasing.
Hope this helps.
Pete