In the connection
Properties (right-click on connection name if it isn't open already) -- go to
Connection details. There is a field for
Proxy server.
Or open the global
Settings dialog (Extras - Settings), and in the FTP pane there is a button labeled
[Define] Connection - default options
It opens up the same dialog, and my guess is that you could define the proxy for all FTP connections there.
Best I can do, having no proxy of my own
