Bernie, to get various kinds of desired modulation on my system, I usually program Kontakt to accept aftertouch from my controller keyboard. It works as designed...very well a that. You can also program Kontakt to provide modulation, e.g., vibrato, on a timed bases, i.e., vibrato starts after xy ms after you first hit the key. In addition, you can set the depth of the vibrato.

Finally, I can program Kontakt and the controller keyboard to send modulation information via the joy stick of my Roland A-37 (I would prefer mod wheels).