Is there a way to modify pitch of a sample by aftertouch??

Hey I was trying things out and learned how to modify the pitch of a sample by velocity, now I wonder if there's a way to modify the pitch by aftertouch. I mean by this to play a sample by pressing a pad but afterwards modify the pitch by the aftertouch pressure on the pad.
Thanx!

*this post has been rendered completely irrelevant because I didn't thorougly read the question.*

I'd say this is not "aftertouch". Aftertouch is a special event transmitted if a key (key on the keyboard) was already pressed (NOTE ON emitted) and pressure changes while still being pressed. As far as I understood the manual the After switches change behaviour when changes take effect.

First of all try to switch on your unit, before posting and test your steps. When I invoke Q-Link menu there's no such parameter like "pitch", only "tune". And aftertouch is explained for example on p.36 of the manual:

The pads of the MPC5000 are capable of sending aftertouch messages to both the MPC5000's internal synth, and to external devices via MIDI.

So there's no chance to have Aftertouch modulate a sample's pitch. (Changing tune or applying an ADSR envelope is done from program's resp. sample's settings, and there's no such thing like an aftertouch mod source.)