You have to understand that pulling on the handbrake while going straight into the corner will not do anything. Even if you are turning into it, chances are that you will just steer normaly or even understeer because it effectively drags the rear.
Proper technique for negotiating a tight hairpin would be to come into the corner and before you finish braking completely, you turn or even jerk (depends on the severity of the corner) the car into the corner and just a fraction later, pull on the handbrake a bit. The ammount of car movement is dependant on your setup, so is the corner exit. You just have to get a feel for it.
For the moments when you are already sliding but you need to turn in more (loose surfaces) just take off a bit of throttle and simultaneously tap the handbrake and then go to power instantly.
I dont know to what excent CM are simulating this, but modern cars like WRC2010, WRC2000, R4, have self disengaging rear differentials when handbrake is pulled, so in theory you can just go full throttle and pull the hanbrake, realease, and the rear drive kicks in again.
Older cars, Group B for instance, afaik had locked centre differentials, which meant no handbrake at all on grippy surfaces as it would block all wheels even with the clutch pressed. RWD cars need clutch, otherwise you are stopping the only drive it has and kill the car. Quick dabs can be done without, but better safe than stalling the car.
Also, it is important to know that handbrake is really useful only for acute corners (to place your car for maximum acceleration) and correcting cornering if it's not going as planned. Otherwise you are wasting time if you use it on open hairpins and sometimes even hairpins.