just have the PPP and KKK buttons mapped to the R & L shoulders, Hard Punch to ( Y ), Med Punch to ( A ), Hard Kick to ( B ), Med Kick to ( X ), and the light attacks to whatever keys you prefer - this is what i do.
Think there might be an issue with the screen detecting finger pressure, mine always responds to stylus better, and its suicide to get the stylus out in the middle of streetfighter.