I found the Windows Configuration page insufficient for getting started in a straightforward way using darcs over ssh from Windows peers to a FC4 repository host.
This Gentoo oriented page was essential in the resolution.
In summary here are the steps which I found led to succesful passwordless login:
- Run ssh-keygen to create dsa file.
- Move public key file to DOS and convert using puttygen
- Move files as directed in second page above in target Unix server account
- Load converted file into pageant.
At this point ssh user@hostname logs in without prompting for password, and intended darc interoperability will work. Besides above I think the only thing I did was enable the mentioned options in sshd_config (did before started working with second page above).