The developer is extremely responsive, you could probably reach out and ask. Typically for scp or ftp I just use a terminal session anyways. You can setup custom connection strings, so you could have a terminal session launch and connect with scp/ftp.

XQuartz might be of interest to you. It used to be included with OS X in older releases but is an external download now. http://xquartz.macosforge.org/

After you've installed it, you can test that it works by typing

    xeyes

in your terminal. That should show two googly eyes.

Then ssh to some other machine with X forwarding enabled. To do that, ensure the remote host has

    X11Forwarding yes

in

    /etc/ssh/sshd_config

then

    ssh -X example.com

Assuming the server has the necessary X11 libraries and xeyes is installed on the server, you can once again type

    xeyes

and you'll see the googly eyes again but what you are actually seeing is them running from the remote machine.

Hope this helps though I'm not sure it is quite what you're looking for.

(Personally, I use X forwarding very rarely, prefering the terminal for almost everything but browsing the web.)