I think it is not possible.
I tried pasting a fully qualified ftp path (
ftp://user:password@host/path/filename ) into the normal Open File dialog and as expected Windows pulled the file from the FTP-server and placed it in the temp folder. And as expected a save file will not put the file back on the FTP server.
Then I tried a small script
UltraEdit.open("ftp://user:password@host/path/filename");
and UE says "... contains an incorrect path"
When I try to use the UE syntax for FTP files but with user/password/host:
UltraEdit.open("FTP::user:password@host\\/path/filename");
it is ignored - no error, and output window says "script succeeded".
So you are stuck with having to create FTP servers and their connection details in the GUI, to be able to open FTP files from script as
UltraEdit.open("FTP::FTPconnectionNameInUE\\/path/filename");
I can see why it sometimes could be handy to open FTP files directly from a script without having to define the connections in the GUI, but it will open up some security issues, as the password will be fully visible for bypassers when it is entered in a UltraEdit.getString box and if working in an non-secure/public environment the password would then be compromised.