I think I now tried about everything that is to be found on the web around "git push" from within a TeamCity build
I tried this: TeamCity: On successful build push to Git Repo
and this:
http://devnet.jetbrains.com/message/5510674
and many variations on this. Every git operation (git add, commit,...) works perfectly but git push always hangs the build. If I do exactly the same in the command line, it works perfectly. And btw Git does not need passwords or anything.
I would love to solve this ;-)