If you have a basic midi controller (as many arranger keyboards are), then you will only have access to the first bank (128GM) sounds. Korg usually goes a little deeper with their keyboards and thus offers more options to control more parameters, access voicebanks .. etc (not found on other manufacturer's arranger units), but these features are available for way less money on professional Midi controller keyboards, such as MAudio ... etc.
Thanks,
If you want to access them from your arranger keyboard, you can also use an ipad as the middle man... in else you send midi from your keyboard to the ipad, and use a program like camelot pro or AUM to send the program and bank change sto the SD1000 trough the midi out..