The BSP drum pads are assigned a MIDI note each. Your drummachine has it's instruments assigned to MIDI notes. There are a few different standards for how to set-out the notes in a MIDI drum kit.
Roland in their infinite wisdom chose to create their own standard that only they adhere to. That is okay, they helped invent MIDI, so everyone just seems to work around them. It can be a real pain with big kits, but the TR-8's kit is tiny at currently 15 instruments with the 7x7 expansion. Seeing as the BSP has 16 drum pads, there is no reason why you can't have all the sounds playable from your BSP drum sequencer.
The BSP comes with the ability to define individual drumpads by midi note. In MCC you can choose to define them using a preset or select each note per pad (custom). Refer to page 85 of Beatstep Pro Manual v1.4.0 for how to do this.
Now here's where it gets dumb. Roland has two different ways they have assigned their MIDI notes depending on if you have the 7x7 samples installed. Here is a list of the assignments Roland have used:
If 7X7-TR8 is not installed:
BASS DRUM: 35, 36
SNARE DRUM: 38, 40
LOW TOM: 41, 43
MID TOM: 45, 47
HIGH TOM: 48, 50
RIM SHOT: 37
HAND CLAP: 39
CLOSED HI-HAT: 42, 44
OPEN HI-HAT: 46
CRASH CYMBAL:
RIDE CYMBAL: 51
If 7X7-TR8 is installed:
BASS DRUM: 36
BASS DRUM 2: 35
SNARE DRUM: 38
SNARE DRUM 2: 40
LOW TOM: 43
MID TOM: 47
HIGH TOM: 50
RIM SHOT: 37
COW BELL: 56
HAND CLAP: 39
TAMBOURINE: 54
CLOSED HI-HAT: 42
OPEN HI-HAT: 46
CRASH CYMBAL: 49
RIDE CYMBAL: 51
If you use the Custom drum map assignments in MCC, you will have all the instruments on your TR-8 included, with one 'dead' pad (perfect for running an analogue gate track).
Hope this helps.
