Can't think of a way you'd use R-BUS with a MacBook. But, as you're posting in the VS-2480 section, here are a couple of ways I use it with mine:
* an Edirol DA2496 to provide 8 more ins/outs
* a Roland MV-8800 to keep data in the digital domain when transferring/mixing
Likewise, you could use it for connecting the XV-5080 synth.