Vortex Sound Research

Just picked up a Yamaha VSS 200, all the keys work, voices, rythms, demo etc. I want to try out the sampling but I can't seem to get it to work. I press the Sample button, and I get a BEEP. Then the display shows "SP". After the beep I scream into the mic pretty loudly. Then I think it's supposed to play back that sample. But it seems nothing plays. After "Sampling" a sound, am I supposed to hear that sound played back after pressing keys?

Maybe there's something I'm doing wrong here. Does anyone have a Yamaha VSS 200 and can they help me get this going?