I have a Alesis QS6.1 64 voice expandable synthesizer. I have purchase a MIDI to USB converter cable and attached the synthesizer to my Power Mac G5 system that is running Mac OS X 10.5.5. The Audio MIDI Setup program on the Macintosh indicates that it successfully identifies the MIDI device. I want to be able to use the synthesizer to record in GarageBand. However, when I open GarageBand v2.0.2 and play the synthesizer sound comes out of the synthesizer speaker and nothing happens on the computer. There is no indication that GarageBand is responding at all to the synthesizer. What is needed so that the synthesizer keyboard will work with GarageBand?