My Career Dunk Issue

Hey guys, I like the new NBA 2k14, but in MyCareer Mode, I can't dunk, I already equipped signatures and others. I tried it in ShootAround, it works but it requires this button to dunk (LF1+RF1+C) like in NBA 2k13, it works for me to dunk, but when I play in a game, it won't, it just throw an alley-oop or lay-ups.. PLEASE help me..

Use only SPRINT button and SHOOT button.