I don´t know the SD1, but if is has got instrument-banks this should be possible via simple revoicing.

e.g.: ( from my Audya, but in principle it´s useable to all keyboards! )

MIDI-Original ( MSB,LSB,PrgChange ):

Grand_Piano = 0,0,1

GM2 Voice instead : Bright_Grand = 0,1,1

For those who have a Yamaha-keyboard : Use PSRUTI (freeware, scroll down for english version), it´s very easy to revoice standard MIDI-Voices by Tyros-Voices.

With the "Midifile Optimizer 7" from MIDILAND ( 150 € ) you can do it as well very easy, it has the soundbank of the sd1 and sd1 + ( and Audya ) built in.