Argh, you beat me there by one day! I've just finished doing the same SPDIF hack to my HU tonight . I guess your Scenic has a VDO "Tuner List" HU too, right?
A few questions about your setup:
- You are keeping the changer connected to enable the HU's SPDIF input. Does this mean you always have one or more CDs inserted? AFAIK, an empty changer is automatically ignored and skipped by the HU when switching audio sources. This is why I bought an aux interface from connects2.com (type VRNX001). It acts as a fake cdchanger and also contains an analog-to-SPDIF encoder.
- Furthermore, how can I get the audio line-in (and the mic input) of the epia to be mixed into the SPDIF output? I haven't tried much yet (nor did I search..) -- all i noticed is that I couldn't hear anything from both inputs. Neither of them is muted in the mixer panel and they are being output properly to the ANALOG line out.
Anyway, congrats on a hack well done. I am pondering a smart PIC-processor based interface so I can use the HU's stalk control to send commands to the PC. The stalk control in my Clio is actually a simple 3x3 matrix of switches. I am quite sure the Scenic is identical.
EDIT: I did a search on the analog input issue. There doesn't seem to be a solution yet. A software pass-thru might do the trick, but it will increase cpu load. Anyone?