Actually the easiest way you can accompolish this by using the step sequencer.
Left click and hold the little tab at the bottom of the Record button on the transporter and select "Step record". Now when you click on the record button with your mouse the step sequencer will pop up.
I always choose a quarter note then check the "tuplet box". you will be able to choose the number of notes in 1 beat. Then place the "now" time marker where you want and use your midi keyboard to input the notes.
That is how I create Orchestral runs....