For support authorship in K2 extension, be sure you are using 3.2 version. In previous version 3.1 wasn't plugin working in all cases. From 3.2 it's fixed.
After days and days looking how to connect my author pages and Google+ manually, I found this nice and light plugin... and wow! it works like magic!
Tested in Google structured Data, searched in Google search and yeah, results is here!