Importing OpenSSH RSA Public / Private Key Pair into Apple's Keychain Access

As stated in the title, I would like to import a key pair into Keychain Access.

What I have done:

1. Obtaining an RSA public / private key pair by using OpenSSH

What I am going to do:

1. Importing the key pair into the "login" keychain of Keychain Access
2. Creating a CSR with OpenSSL
3. Send the CSR to Apple for obtaining a developer certificate

Any suggestions are welcomed.