Since you're going to have a DD2.0 track, I'm surprised you didn't favor the idea of extracting the DTS core... because that's just awesome stuff (and one of the least difficult things to do with eac3to).
I don't know if you saw the Wiki for eac3to: http://en.wikibooks.org/wiki/Eac3to/How_to_Use
Anyway, if BD-RB didn't turn out satisfactory results, let me know, I could probably do the conversion for you.