the following will mess up your RedHat installed start/stop script. So RedHat will probably complain the next time you try to do an update -- it'll see you have the RH sshd package, but your start/stop script will be altered... you need to understand what you're doing when you try the following:
look at the /etc/init.d/sshd shell script. On RHEL, this is the "controller" script used by init to start/stop ssh. There are several variables set at the top. I would create a *new* directory -- don't use /etc/sshd, the standard RHEL config location -- to hold the config of your freshly installed sshd. Maybe /etc/sshd_v1.4 or something...
stop the sshd (as root '# /etc/init.d/sshd stop') before you edit the script. DANGER: if you are connecting to the system remotely, keep an extra login screen off to the side. If you stop sshd and log out, you will need to go to the console. Refer to chkconfig(1) for info on how sshd is auto start/stopped at boot/shutdown.
Then adjust your init.d/sshd shell script. Change the KEYGEN and SSHD variables to point to the new ones you installed. Update all the instances of /etc/sshd/ to reflect the new config dir containing your configs for your new installation. (I would start by copying the entire /etc/sshd/ directory if your new install didn't make you a new config dir somewhere.)
after adjusting, start it up: '/etc/init.d/sshd start'