Here's a better solution. Yet, this is within both of the manuals. However, many people that answer with sarcasm always hide this fact: they don't know the answer.
With in the S950, create

64 keygroups. The keygroups will be listed as note numbers and keynames-per-octave (i.e. C0, D0, etc). These keygroups will correspond the the 64 pads of the MPC. The MPC will tell you the note number of each pad.

Match the note number of the keygroups to the pad. (example Pad A1 = #60, make keygroup-1 = #60

Sidenote: actual number values are in your machines). It might vary with each of the MPCs and may differ is using JJ-OS with certain models.
If you don't care about the MIDI channel the S950 responds to, set it to OMNI. Else, set it to Channel-10, or whatever the default channel for drum is via General-MIDI (requires some reading, studying, and research on your part). This will still allow you to use the other channels for your self made patches/programs. From the S950 manual, both book for and the S900 video manual, set the MIDI channel to the number you want it to respond to minus one. Else MIDIChannel #1 = 0. This unit was first made when electronic musicians knew much about computers and did not rely heavily on WYSIWYG. It also makes perfect sense because ALL COMPUTERS start counting with the number zero.

Sidenote: notice that the velocity parameters are from 0 to 127?
I hope this will help. Yet, after making such an expensive investment, you should always READ THE MANUAL first or as you are learning how to use anything. NOTICE HOW MANY PEOPLE THINK THEY KNOW WINDOWS, then cuss out people at Best Buy because of their ignorance and their arrogance. Unless you want to be an equal, read your manuals, don't be a sequel.
Mad Cherokee