I think it's a case of making sure that the pedals either actually DOES address the same Part that you are playing from the keyboard (which it doesn't, usually, coming in from the MIDI input), or finding a way to edit the Part it IS addressing with the sustain and so forth commands to get those on the bass part.

Do you have another MIDI keyboard you can send into the MIDI port to see if (when set to the same MIDI channel) you still get the same sound...?

What you MIGHT have to do (I've not done this myself, so take this advice with a grain of salt!) is set up a Sequence, with the Bass sound and parameters set the way you want (possibly Makeup Tools can get to the Sustain and effects parameters you want), and Link it to the UPG you are using.

But I could be totally off base, here. Derek Miles, I think, at roland-arranger is our pedal guru there. Maybe he can help you?

But my feeling is that the pedals are NOT addressing the same Part as you play for M BASS on the keyboard, and this is why you are hearing something different...