The cause of this is in the hardware and is not a OS based issue.
Some measures can be tken to either reduce or eliminate the effect. To do so we must modify the the Fusion's velocity curve.

Go into the Fusion's Global menu under Settings>General and then select Set Velocity and change the parametes from Lin, Exp, Fixed or Lag until the best option is found for your style of playing is found.

A global velocity scaling of 50 seems to work well with external sysnths and sound modules. It is also suitable for playing internal programs.

Another method to control or modify the velocity a external device or software utility could be used such as a MIDI velocity converter box or a program such as Velocity Curve Changer from trombettworks.com