I'll take a look when I have time. Otherwise, I know you're a member at AVS, so why don't you post there?
http://www.avsforum.com/avs-vb/showthread.php?p=16230487
I hope that you can get the secondary with mch analogs.
Ya know, you can also try a secondary optical connection, with other settings... just for situations like this. of course, it'll all be lossy, but so what. It's PIP.
Ok today I tried to use the PiP just to see what it is like.... Well after 1+ hour of playing with it, I am here & need some help. I get the video but no 'Secondary Audio'... movie Resident Evil: Extinction
Setup:
HDMI stright to TV
5.1 analogs outs to reciever Yamaha RX-V1500
HD audios both set too PCM
Dynamic range compresstion OFF
PCM Down Coversion OFF
Downmix Stereo
High Clarity sound Disabled
Analog Audio Output: 2ch (downmix) + 5.1 ch (back speakers turned off in the speaker setup area)
BD-Video Secondary Audio On (I normanly have it OFF)
No SD card installed
From reading the manule I should get 2 channel audio when I hit the PiP button but then the manuel is not written very well.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic