Quoting Ian:

"Seems the S910 may be using the same type of organ tone generator as the Tyros3"

Seems that way Ian. Looking at my Ty3 the Release setting for the Cool Organ voices is generally -24ish (-25 in one case), but Organ-a-gogo is zero and JazzOrgan and Organ are just -4. So the 3 latter will react OK to the sustain pedal.
There seems to be little consistency with the SA organ voices too- some Releases are set at o, so will sustain, others are set at -24 and won't obey the sustain pedal.

John