I don't know how "technically inclined" you are, but if you want to do
a bit of debugging of what WMC is exposing for the lossless tracks to
your media playback device, you could download the "Intel® Tools for
UPnP Technologies" from
http://www.intel.com/technology/UPnP/download.htm#tools

Included in these is an "AV Media Controller" which can browse through
the catalog exposed by the media server software (ie WMC in this
case), and you can look at the actual attribute information that is
exposed for each track. It might - or might not - be instructive to
look at what WMC is showing for both the lossless and "normal" WMA
files, and whether or not the lossless one looks like it might be
adding/missing something that your player device doens't like.

You can also do the same with any other media server app you might
install (eg there is a "reference" on in that same kit from Intel that
you can test with too, as a "cross check"), and see if for those there
is anything sigificantly different with how the lossless WMAs are
exposed to the player.

If you can find a difference, between how the lossless WMA file looks
on a server that works end-to-end to your player vs how the same file
is exposed by WMC, then I'm sure that is the sort of thing that the
Microsoft guys reading this newsgroup would be able to take to try to
repro in their lab then fix in the next release (with any luck).

ted.h.