... cannot not use keys ... I just don't know enough about how use the pty. so that i can start another ssh session and pass the options I need

Did you try something? What happened?

I would do  system qw[  thenewprogram.pl usrname password whateverelseiyouneed  ]; ...

or Proc::Background if needed

And inside thenewprogram.pl just do regular old   Net::OpenSSH->new('username:password@hostname.example'); ... error checking ...

and ...