In my current plaything I've got YPbPr, stereo audio, coax and composite on the console with one switch to toggle Advanced AV (mode 2) and HD (mode 3) - which basically just toggles the composite and YPbPr, coax and stereo audio work in both modes. I've bridged the pins of the second switch in the diagram (pin 11 and 12), and use the switch to pull either pin 9 or pin 13 to ground for Advanced AV or HD. You don't need to touch their respective sister pins 10 and 14, with a multimeter you can see they just go straight to the system ground.
I've actually just resoldered all my connections to the motherboard with shielded wire and mucked something up that I haven't had time to diagnose yet (possibly because I got cocky and tried to pull all the RCA jacks to a common ground too...), but I had it working lovely a couple of weeks ago just with a little bit of snowyness from cruddy wire.
Some photos of the glorious time when it worked can be found in this imgur album:
http://imgur.com/a/jtI2o
The solder photo with many wires is only the AV lines, you can see the bare midsection which are the mode selector pins. The solder photo with less wires is my resolder with everything, except with no ground lines as stated previously - AV connections are big thick black wires, you can see the bridge on pins 11 and 12, and the green wires run off to the switch. Apologies it's not that well done, I was rushing it haha, basically pulled most of the previous connections off. Oh, and the photo of the rear was taken right after I finished dremeling the holes and popped all the connectors in to see what it looked like, hence the dust everywhere and general sloppyness. Yes, the blue RCA is wonky in the photo, but isn't anymore.
The silver switch in line with the connectors is the AV mode selector, you can probably see the hookups in some of the shots, but I pull +5v, +3.3v and Ground from the motherboard PSU connector and hook them up to a breakout board, and the common pin of the switch is connected to ground there with a trailing wire, and the other switch pins are pins 9 and 13 on the AV.