First off let me say this is my third Volvo. I l ove the brand and understand some of teir quirks. I recently purchased a 2011 XC90 with a V8 and their indash navigation system. We had the delaer install the factory rear seat entertainment system with the monitors in the driver and passenger headrests. I don't know if the system is broken, or if it just sucks. You can put a dvd into each player/screen. I cannot toggle both monitors to play one dvd, or theother. the driver monitor will only play what is inside its dvd slot. It will not play what is in the passenger slot. The passenger will play either.
Also, we cannot figure out how to play the volume through the car speakers vs. only through the headphones? we have a 2.5 year old who won't wear headphones yet, and he goes without volume, for now.
Just venting here, but is the DVD navigation system just the worst navigation system ever? I cannot believe how cumbersome and non-intuitive it is. Whe we go on trips, we take our portable Garmin.

 

I have the duel screens, but ours doesn't have two separate dvd slots, it just has a main one that is under the front seat armrest. So i cant help you with that. But to listen to the sound for the video through the car speakers, i just use the sound selector **** and set it to AUX and then make sure the AUX/SRE button (found in the front seat cup holder area) is set to SRE and it should work.

I too do not care for the nav system. Its just strange, i wish it were touch screen.