Well you got one fundemental problem.
There's no way you can get somebody to download a file without sending the location of the file to the browser.
It always has to download from somewhere. You could maybe do something with an active x control but don'tknow much about that
I would suggest using dynamic linking. The link to the file can only be called one time.
I've seen that being done but wouldn't know how to do that.
Not very helpfull but goodluck!