Jorge,
Here's his fix:
The iPad will only output from 1&2 on a USB device. The reason why you're not hearing anything out of 1 & 2 is because the 1818 defaults to "volume off" on output 1&2. It's an easy fix -
1. Plug in the 1818 while Auria is running
2. Once you see the USB indicator on top of Auria's screen, turn up your iPad's hardware volume control (located on the side of your iPad). This control adjusts the 1818's 1&2 output volume.
3. This only needs to be done once, as the 1818 will remember this volume setting.