I'm new here and just installed the trial version. Let me addendum this with I'm using a very powerful desktop computer with other virtual pianos which work fine. I went through the set-up and did all procedures as required but there's hardly any difference when I push on the sustaining pedal when playing. Maybe only a marginal change at best. I have a Roland HP508 which works fine overall and certainly works with other vst software. What am I doing wrong?
Have a look at your Pedal response curve (click the left/right arrows at the top of the Velocity panel) and the values your keyboard is sending when you depress it by varying amounts (these show up as green vertical bars superimposed on the curve). You can calibrate the curve manually so that when the pedal is fully depressed the output value (vertical axis) is at maximum (127) and when it's fully released, it's at 0. Or click the Calibration button under the Velocity panel which will launch the "Calibration Assistant" that takes you through a guided step-by-step calibration of the keyboard action and pedal.
If the Calibration Assistant does not work correctly, it's most likely because your keyboard is sending High-res MIDI but Pianoteq is set up for Standard MIDI. Then you will first have to change the MIDI Dialect: Click Options -> MIDI -> Dialect -> change from "Standard MIDI" to "Hi-res CC#88". Save it as a new preset by clicking the button next to "Current MIDI Mapping".
Also see chapter 10 of the manual for a brief overview.
Thanks, SteveLy. I had no idea that feature existed. Now I've finally been able to do a full calibration of my Casio Privia 850, which uses Hi-res MIDI.