community builder and k2 do not integrate users

I am using latest version of k2 and community builder but found that if I use community builder login form, then the user is not created in k2 user table and this prevents users from uploading pictures to k2 profile. Also when a user adds a comment in k2 articles their profile pic does not appear and their real name appears instead of their username. Does anyone have a work around for this or know any extensions or bridges that fixes this integration issue...it would be greatly helpful...thank you,,,,,,