The purpose from this way is that you can still use external audio processor that Zara don't have.
This is what should you do to streaming Zararadio to MBL4 standalone audio processor :

• Set Virtual Audio Cable (VAC) like this example

If you don't have Virtual Audio Cable (VAC) you can download here .
This is the picture.

• Set all Zararadio output to virtual cable.

You can set in Tools->Options->Output
If you don't have Zara Radio you can download here .
This is the picture.

• Set Virtual Audio Cable (VAC) hardware sound acceleration level to "Full"
  Open Direct-X Diagnostic Tool by Run Menu->dxdiag->Sound 2
  If you don't set this hardware acceleration, it will cause high CPU Usage.
  This is the picture.

• Set input device MBL4 to Virtual Cable 1 and Set output device to your real soundcard.
  If you don't have MBL4 or Sonos II youcan download here .
  This is the picture.

• Play MBL4 and Zararadio