Sending two selected files to a diff application

I usually find myself in need to compare two files (one local and one remote) with my diff application. Currently what i do is to view the remote file to copy its contents and paste it to the diff interface manually.

It would be awesome if flashfxp downloaded the remote file and sent it to the diff along with the locally selected file. There of course should be a configuration option where we set the command line and file-path arguments for our preferred diff app.