I'm probably going to get in heaps of (technical) trouble for this, but I also have the box set. I actually completely forgot that it came with several of the Streamline dubs as the second audio track. Be warned that the Streamline track is in mono.

The only way I have to capture the audio is to run it to my DVD-recorder. I'll have to double-check, but I think I'm running optical out to the recorder (if that makes any difference).

Probably not the best solution, but there you have it. Oh, my LD player is a CLD-R7G. A thing of beauty.