- To get the latest fixes I would recommend you to upgrade to beta5 or RC1 (not sure the exact name), which will be released on this week. This should make "DTS test" work, and I suggest you to continue tests with it.
- The ALSA output device (virtual) for writing to the SPDIF should be "asym_spdif", so try putting it in the Amarok configuration settings (LinuxMCE itself doesn't use Amarok, so you should configure it manually - http://opensusenewbie.blogspot.com/2007/04/how-to-get-amarok-and-kaffeine-to.html
, but use "asym_spdif" instead of "plug:spdif").
Regarding #3 - don't know yet, please retest it after upgrading.