Roland S550 with MPC 2000 Classic

Hey there! I got a Roland S550, this thing is is really cool. I love the layout, the sound blows my mind. But I am having some problems sequencing and replaying. I am sequencing with the mpc. The odd thing is that no matter how I configure the channels I can only get one sample to play at a time. If someone could enlighten me or even probe me for more information. That would be awesome. I'm bad at starting topics haha. I do need some help figuring this stuff out though. Never used a rack mount sampler before.

Anyways thanks in advance.