Well as I understand it this issue is due to limitation in the bitstream process or how you would call it. It seems like that it's not something that can be fixed. Google it and you will see.
Although I believe few people can hear any difference between the two decoding options, maybe, just maybe you could with multidollar equipment and a trained pair of ears.
Also as BR players are getting better I think any difference will become smaller and many people like to use the extra features that are available with PCM. Especially considering the fact that PS 3 is the no 1 BR player right now, and it can not send high def sound as bitstream.
http://www.avforums.com/forums/showthread.php?t=797122
