I\'ve searched and searched, for what seems like hours, for a solution to this problem and nothing I\'ve tried works. Let me preface all this by saying that while I\'ve use
I had the same problem recently: I could clone/push to my gitosis-managed repo from Cygwin, but TortoiseGit kept asking for the password of the git user (git@192.168.1.30).
Finally I could make it work by reinstalling TortoiseGit (I selected the Plink option at install time), then on the TortoiseGit settings go to Network > SSH Client and change the value to your Cygwin ssh binary (ie. C:\cygwin\bin\ssh.exe).
By changing this I was able to do all the operations from TortoiseGit, and I'm asked for the password the SSH key which I defined on Cygwin.
Also, check that your gitosis.conf contains the public keys which are visible to Cygwin, removing the ".pub" extension: if my Cygwin install shows that I'm myuser@myhost, the associated entry on gitosis.conf should be myuser@myhost and the file with the public key should be on keydir/myuser@myhost.pub