OpenSSH with windows server 2003

Hi people,
I'm trying to configure the OpenSSH in my win server 2003 to accept connection with public/private keys, without password.
I research all over internet sites about, almost all them, have the same instructions that doesn't work.
I can just get a sFTP connection with password without private key.
Do you have any idea how to configure my OpenSSH to accept a SCP ou sFTP connection with a public/private keys?
Please, i lost almost two days trying to do this.

Thanks!!!