This is Theodore from Greece. Turning off velocity response is very easy, in fact you can specify a fixed value for velocity no matter how strong you press the keys. Here is ho to do this:
1. Go to "System" mode
2. Select the "Keyboard" page (button 3 on the Tone Switch menu)
3. There you can find the settings for Transpose, Sensitivity, Velocity and Aftertouch.
4. Regarding Velocity, set "Sens" to Light and "Vel" to 127 (highest). This should do the work. Bye!
_________________________
Unicorn