Running RMAN backups from grid control but using oracle account with rsa keys vs a password ?

I'm a sysadmin trying to help out one of our DBA's setup the RMAN backups (Oracle 11g on rhel5 ) so they can schedule and control them from the OEM grid control. But we want the oracle user to use ssh keys instead of a password. I have the working rsa keys in place for the user but the GUI seems to require a password and all tests fail if we do not specify a password. I've looked around and been unsuccessful finding anything to resolve this so far. Is this something that can be done or does the software require a password ?

Thanks for your help.