It is one thing to rocket up to 10 miles altitude - an entirely different thing to get up to 62 miles altitude.
Need more thrust, more burn time, better ship attitude control, and all that fun stuff. It may be why Rutan is retired to the Idaho ranch these days- he is no rocket scientist, just a good airplane designer.
Good luck with that new chunk spewing, nozzle-clogging plastic motor there, Virgin guys. You are going to need it.