Calling Push To... the dialog does not have the option to add --mirror
I also tried with the GitBash but i cannot authenticate (i think it's not
working because i use SmartGit as SSH agent, i already cloned a project
with SmartGit from my BitBucket account so it seems to be configured fine)
> Calling Push To... the dialog does not have the option to add --mirror
You should not need the mirror option in your case as it's the only remote anyway. Just push all your branches and tags to the new remote. This is the same procedure as given in your link, a couple of paragraphs up ("Already have a Git repository on your computer?").