Yamaha THR10 II / Cubase AI How to record dry signal from THR

Hi - I just bought a new THR10 II which comes with Cubase AI. I can record the amp’s wet signal just fine using the Generic ASIO driver. When I select the “Dry Mode” on the THR, I no longer get audio. Somewhere I read something about the dry comes in on channels 3 + 4, but I can’t see how that works, or how to set that up. I would really love to be able to record wet and dry tracks if possible. Any assistance would be greatly appreciated! PS - I also have ASIO4all driver on my PC if that is of any use, but I did have to screw around alot just to get the Generic driver to work, so would like to keep that if possible.