Found this thread via a Google search looking for where to pick the bus up at YUL - thanks for that info.
Cannot confirm about Miles although it does have a KL flgiht number (KL0301 for the 1830) as I am not taking it until Oct 14th. Can however confirm that it is bookable from Europe (well UK), on a through ticket, by simply searching for Ottawa or indeed XDS when looking for flights. Interestingly when I booked it was actually cheaper to book through to XDS than YUL itself (!). Also in my mind safer than using VIA as the current conenction from Montreal to Ottawa is I think a little short for the last VIA on a Sunday - at least as a through ticketed "flight" any connection problems are KLMs.