I'm pretty sure there isn't a mixed mode, I haven't found it in the options for the Wii U and I doubt that it outputs both (lazy programming with processing power considerations)
..unless you have an SD TV, and using HDMI isn't an option.
Here's a picture of the back of a Wii U. The "video out" next to HDMI is where you'd plug in the component/composite cable. Does anyone know if it's the same as the Wii?
Problem solved:Any advice? I'd rather not spend $50 on a splitter box, would SPDIF do? Or are there cables that branch off of HDMI to audio?
If you have a Wii A/v cable, it'll work on the Wii U. Not to mention, if you need the cable, they run for 4$ on ebay