SFTP and DMZ boxes

Hi
I would like write a script that will do sftp frm a box that resides inside the FW to a box that resides in DMZ.Any ideas guys.I tried generating rsa keys for a particular user, however just want to know is there any other solution or not. Your help is much appreciated.

Thanks
CK

What problem do you have? Our FW is setup so we can connect from inside the FW to the DMZ boxes. Does the ssh key not work?

I dont know about ssh.Can you give me a brief example please..