You can question all files and folders trough the following code:

    DirectoryInfo info = new DirectoryInfo(@"C:\");
    foreach (FileInfo file in info.GetFiles())
    {
        Debug.Log(file.FullName);
    }

Then get a filestream of your wanted file using

FileStream fileStream = new FileStream("Path here", FileMode.Open);

And use that stream in your upload. Dont forget to import http://System.IO.

(This code is C#, as far as i know you cannot do this with Javascript)

Can anyone tell me how to upload a scene file through Winscp? How should I save the file? I am having maximum trouble here.