Yeah, I think he has the output selection wrong in RB.

If you can see the input from the Nord on the VU's, you can record it (success on the input side).
Check your output selection in Options-Preferences-Audio and select the correct main outputs to the saffire. Make sure they highlited and use the 'move selected device to top' button to make them the defaults.

The difference between RB and BiaB, as far as generation backing tracks, is that you have to tell RB to generate. It doesn't autogenerate on each play as BiaB does.
The benefit? You can generate just a single track or even a couple measures of a track when you want to. Or select a few tracks to regenerate.. more flexible this way for me.

I do not work here, but the benefits are still awesome
Make your sound your own!