force video remux and only DTS transcode to AC3

[maurer]

I've already asked this but i'll repost here.

you can delete the other one:
viewtopic.php?f=10&t=1719

Can you help me for mencoder to remux all video to MKV (-ovc copy from what I've read) and only transcode audio DTS to AC3 (for my LG TV).
Also I want it to embed attached subtitles.

I've tried but without success:
mencoder_codec_specific_script = acodec == dca :: -ovc copy -oac lavc -lavcopts acodec=ac3:abitrate=384 -channels 6 -mc 0 -noskip

thanks