SKY only barely support DD so I can not see any circumstance where they would use DTS audio especially as it requires a higher bitrate than the equivalent DD soundtrack.
DD is also the default audio format for High Def broadcasts which are being used in Europe so another reason to perfect DD support.
Never lost sound with DD soundtracks myself but since the last OS update it all seems to have died down implying that the problem has been solved.
I have heard that sky are in talks to supply DTS encoded movies and trying out software and are in trials. It didn't say whether you will need a new sky+ box when it comes out. I can't remember where I saw it but it might of been What HI-FI.