ssh-1.2.30

Hello,

I packaged ssh-1.2.30 without including
/etc/ssh_host_key in it because it is suppose to be
host-specific.
My question is how do I automate ssh-keygen ?
I know that ssh-2.4 you can use ssh-keygen -P and
it will make the keys without prompt for paraphrase..
How would I get the same result for ssh-1.2.30?

Thanks,