iPC and Roland SP-404

I wanna control a sampler (Roland SP-404) with MIDI from my iPC.

I'm a noob with MIDI and want some help with midistrings. I have the HEX values for those three pads/notes i wanna start/stop; 0x47, 0x48, 0x49.

I try with MSh1/0x47, but that doesn't work. Someone who can help me?
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