[boost] [modularization] Trying it out doesn't quite work?

OK I'm following https://svn.boost.org/trac/boost/wiki/TryModBoost Git clone proceeds OK, and I seem to have everything I should have, likewise bootstrapping b2 proceeds OK. But: b2 headers does nothing at all. Trying: b2 --with-regex results in all the expected compile errors 'cos the headers aren't found. What gives? Thanks, John. PS this is on Windows Vista.