A little more digging and I found this in a response on the superior line forum by John Rammelt @ Toontrack.
When it comes to creating a MIDI preset on the MIDI In/E-drums page, it isn’t required that you have an E-drum kit. You can map the incoming notes from your keyboard to the notes you wish to trigger and save this as a MIDI preset. If active, it will not change when switching Library Presets. The benefit of creating your own MIDI preset is that you will still be able to use Toontrack MIDI.
Now, it gets a bit more complicated if you drag Toontrack MIDI to your DAW and still have your preset active but if you only are working on the SD3 Song Track, recording your own MIDI as well as combining with Toontrack MIDI, you will be fine.
I suppose I’m stuck in the “it gets a bit more complicated” part.
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