Despite my pointing this out to LH Customer services, many many routes ex-BRS do not have any fares loaded to them.
In the absence of specific fare basis, the site falls back to standard IATA Y fares, which are frankly crazy. (And if I remember correctly, LH said somewhere that they would no longer honour IATA Y fares from Summer 08, so chance are it wouldn't book anyway even if you were that bloody daft).
I'm booking most of my stuff through fare combining, which is ridiculous, and requires tools like expertflyer and an informed knowledge of fare rules.
I'll poke someone, again, and see if they can get something going. In the meantime, we'll wait for it to grow organically. It does take time....