Dan 2000,
please check this topic I have posted in the General Arranger Forum:
http://www.synthzone.com/ubbs/Forum37/HTML/004891.html

besides, if you subscribe to the Solton Yahoo Group
http://groups.yahoo.com/group/solton/

in the "Files" section you will find a couple of sounds to download (a Hammond organ and a Minilead sound); the Hammond organ has a loop noise in one of the samples, but otherwise they load just fine and this proves that it's possibile to transfer sounds into the SD1. I have already downloaded and registered the program "Awave studio" mentioned in the above link and it seems to work well.
So I think that it's just a matter of proper conversion of the samples into a format that the SD1 can read well.
Andrea