Squeak,
I'm at home now with my owners manual but not the keyboard. It seems that you start with a voice and then edit that voice. I don't see parameters for getting into individual waveforms (samples). What I see are parameters like filter Brightness and Harmonic Content. EG (attach, decay and release). You can select a touch sensitivity range for playing response. Individual effects and EQ can be programmed. However, I don't see parameters that would allow you to program this 2000 like a Motif or a S80. I don't think this is an issue for most customers in this type of keyboard or in this price range. I just found a paragraph at the beginning of the Editing Voices chapter that probably states what I've reported to you.
"The PSR2000 has a sound creator feature that allows you to create your own voices by editing some parameters of the existing voices. Once you've created a voice, you can save it as a USER voice for future recall." Editing SOME parameters and EXISTING voices are the keywords here! I hope this helps.
George Kaye
Kaye's Music Scene
Reseda, California