How to tunnel an SFTP connection over SSH in Dreamweaver?

My situation:
Dreamweaver MX 2004 (7.0.1)
I must connect to a gateway server using SSH. From this gateway
server I can establish a SFTP connection to the web server. But this
is in a terminal session and now I have to upload my files one by one.
It is not possible to directly connect tot the webserver using SSH or
SFTP. I must connect through the gateway server. Any ideas to help
me?

Thank you very much!