The Push Advanced trick didn't work for me. The only way I can seem to do this on SmartGit 3.0.6 was:
- Remote -> Manage Remotes, then click Add and put in the details of the remote e.g. 'master', 'https://github.com/SomeCompany/SomeRepo'.
- Then click Pull. It will say that it can only update submodules
blah blah, hit OK. The Fetch will output a warning "no common
commits".
- Now go to Branch -> Branch Manager. Right-click on your local
branch and choose Set Tracked Branch... then choose the
appropriate remote branch.
- Fetch again. Properly this time.
- Finally do your push to the remote.
It's quite an achievement for a GUI tool to make something less intuitive, but SmartGit does an amazing job of it here.