The multiple switched pedal seems to work well for you, my friend.
I have used a similar rig by Yamaha on the Tyros, can't recall the model number off hand...tried it...dismissed it.
{edit to add}..now I remember...it was an MFC-10 Programmable MIDI Foot Controller.
I'm pretty sure it will work with the S910 as well (I believe the PSR has a midi template all set up for it), but, again, I only want to use one pedal...sustain.
I'm a "hands on" kinda guy.
[This message has been edited by ianmcnll (edited 11-03-2009).]