Apparently you can extract piano parts form commercial MIDI files and create your parts based on that style.
Just for clarification so that someone doesn't read something into your statement, you can cut up midi files and then use them as a basis for modification inside of EZkeys. This isn't any kind of automatic thing.
Some folks have misunderstood that EZkeys works something like Band In a Box, Jammer or Jamstix and have been disappointed.