Yeah, to pedal kick you have to use 1 finger on the brake so make sure your doing that! If you can back hop, when your on the back wheel practice just hopping on the spot a few times till balanced and then just lean slightly forward and give a slight kick with your stong foot. You may not get air but even if you just wheelie and brake repeatedly you can add the jump in.
Alternatively start by rocking from front to back wheel only coming about 1cm off the ground either end and then when balanced next time you rock backwards, give a kick on the pedal. Thats how i learnt, then you just take the technique forward and do it from stationary, then when you can do that, try from rolling!
Hope this helps, Jack hey, just saw that you said you have trouble taking your finger off the brake - i would recommend that get hopping on the back wheel and then practice taking the front brake on and off in time with when you hop. Then start doing it with the back, this way if you do it wrong you wont end up hittin the deck! Doing larger hops when you start on the back brake will help as you'll have more time to get re-apply the brake =)