Use SPDIF as passthrough on lindy usb audio pro adapter

I have a notebook with HDMI output, and enough horsepower to play blu-rays and HD files on my TV. I also have a DTS/DD Yamaha amp, bought before HDMI came into vogue. It has coaxial and SPDIF connectors: in order to play BDs with HD audio one has to rely on the downmixing to DTS/DD provided by the software player (the TV can handle some downmixes with its toslink output, but it doesn't always work well): so I need to add SPDIF out to my notebook.

I already have a Fast Track Pro M-Audio usb interface. It has coax spdif, but at least on my system, whenenever I try to enable spdif out an downmixing from PowerDVD, the computer crashes spectacularly with a BSOD. I looked around for a cheap solutions and I found the 'lindy usb audio pro adapter' - it's a usb audio dongle based on the C-Media CM108 chip. The headphones port doubles as an optical toslink port (there is a red led behind the 3.5mm jack connector, and an adapter jack is provided). The only trouble is, once the provider driver are loaded SPDIF works, but only in PCM mode: the driver doesn't expose any SPDIF pass through capability to software players, which thus can only output 2 channel audio. At least on my system whenever the lindy dongle is used as a default audio device PowerdDVD crashed again, albeit without a BSOD.

The solution: well it's of course a driver problem, so one has to change the driver. C-Media and lindy seem particularly secretive regarding their latest drivers, but after a bit of searching I found  this. It's supposedly a "TerraTec Aureon Dual C-Media CM-108 modified Windows 7 Driver v.7.12.8.2144 for multichannel bitstream output". Different card, same chipset: it's an unsigned, patched driver, but it contains no malware, and on W7 64bit, it enables SPDIF like it should be on a small, cheap audio device.

UPDATE: Look here: http://akizetagamma.blogspot.ch/2012/08/gunstigste-moglichkeit-spdif-ausgang.html for instructions on how to patch the driver yourself, it's in German, even if you can read it should be understandable even automatically translated.