Casio CZ/ VZ/ FZ - Pro Series

Hi

im thinking of getting a volume- and a sustainpedal for my CZ1. The 
manual states Casio VP-2 and SP-I pedals, but these models don't seem 
to be in production anymore. 

So I wonder what other pedals I can use. Does the available Casio SP-
2 sustanpedal work the same way as the SP-1, or is it using a 
different interface method, not suitable for the CZ1? ... and what 
with a Roland, Korg or other brand of pedal?  

Is there anyone here who knows how such a sustainpedal actually 
work? - is it simply a switch that makes a connection, or is it more 
complicated, like theres a specific resistance needed. And if it is a 
switch is it working in latch or unlatched mode?

Volumepedals - I know some volumepedals, like the ones you use for 
guitars, are active  attenuators, working on the output audio signal. 
I could get one of those, sure, thats no problem, it might even be 
the best solution, as I could use it with other instruments as well.

But the Volumepedal that goes into the CZ1 obviously can't work like 
that. I guess it must be either someting like a variable CV source, 
or perhaps just a potentiometer working in series with the main 
volume slider. Unfortunately the manual don't give any specs of the 
interface, if its analog or digital, passive or active. 

It could be very interesting if it was a simple interface using 
resistance or CV, as you then, somehow, could interface it with other 
stuff like analog synths - to make tremolo or gating effects on the 
CZ1 sync to a LFO, envelope or evelope follower on a analog synth 
like my Korg MS20.

hopefully -
Ulf/WolleWolfson