In the COMMENTS section following this blog
There is an interesting discussion on Vitamin K and K2 including some speculation on the ability of our bodies to convert from K1 to K2 in the presence of a higher vitamin D status. Bear in mind the original work was done on rats (and we all know they use D2 and are nocturnal so have a different vit d economy)
Stephan has written a lot on Vitamin k2
so it's worth doing a search on his site and reading the other posts as well.