HOW DA HECK DO U DO RC SHORT SCISSOR KICK?? FINGER POSITIONS? TIMING? ANY ADVICE WILL HELP… 
charge back, roll, forward+let go of lk while still holding lp.
Im using a MAS stick but this should work with what ever your using. I use my index to press jab and my thumb to press short for the roll. Now when i rc the short knee press, charge db, then do a half circle like motion to complete the move. For the botton inputs, you should press the roll about when your down, or down towards. Now what i do is i slide my thumb off short by moving it to the lower left of the stick (it is a natural hand motion too.)