I looked into my copy of the DX1 manual, DX1E_1.pdf,? and found a section 5-3 Performance memory parameters (Function Control). By selecting Bank 5 (F5), job 3 Sustain Pedal Assign (see Page 37) you can turn the sustain pedal's usage on or off, and I would suspect that if it were off you would get the voice's default for sustain.? You may have to use STORE PERFORMANCE to either a cartridge (which might have to be specially formatted to take performance data as well as voice data) or a MIDI dump.
