The standard midi continuous controller for a sustain pedal is CC#64. 

If you may allow me to ask some questions, perhaps we can get to the bottom of your problem.

Are you able to confirm that your Kurzweil keyboard is sending CC#64 information? One way to find out, is to look at your midi interface, if you have one;  by depressing the foot pedal, do you see any LEDs become visible on your midi interface?  Another way to confirm midi output:  if you own sequencing software, you might try putting your program in record mode, and then depress the sustain pedal a few times.  Does your sequencing program show that you have recorded Midi CC#64 on/off (127/0 value) messages?

Just by chance, is there more than one foot controller jack available on your keyboard into which you can plug in your sustain pedal?  For example, if I plug my Yamaha sustain pedal into the wrong foot controller jack on my Roland A-80, my keyboard does not send CC#64 messages -- and no corresponding sustain pedal response.

Just being curious, does your CC#64 pedal controller work with any of the keyboard's internal piano sounds?  This is a check to ensure that your pedal controller does seem to work with your keyboard.

If you drag a midi file into the Pianoteq GUI, (assuming that particular SMF contains CC#64 information), does Pianoteq's sustain pedal seem to work?  This is a check that Pianoteq does respond to sustain pedal messages, once sent them.

Hopefully by investigating these questions, you may be able to pinpoint the source cause of Pianoteq not responding to your sustain pedal.  Surely, other Pianoteq members will chime in with their suggestions as well.

Cheers,

Joe