Assign velocity to volume (or anything) in Vacuum, et al

[deepfrequencies]

Hi, sorry if this question has been answered, I looked around but can't find a resolution anywhere....

When using the new AIR soft-synths I try to change the volume of individual notes by manipulating the velocity height under the piano roll, but it doesn't seem to affect the volume of the note. In fact, it doesn't seem to affect anything. I can't figure out how to assign velocity to anything on the vacuum or on any of the new soft-synths.

What am I missing?

Thanks :)