You could manually change each note in the Piano Roll by using the velocity tool on each note.
using the volume in Hyper Draw create a crescendo by drawing two nodes (one at the beginning of the region, one at the end) and positioning them appropriately.
You could also use the Transform window to create a crescendo in a region.
Select the C note in the piano roll, choose: Edit > Select all following of same pitch
then change the volume level with the volume tool.