With the new release of version 1.10, I can use some simple javascript to redirect the user to get the file. I put this in the "Additional Settings" window.
on_sent_ok: "location.replace('http://myurl?getfile=#');"
It works great! The form is submitted, email is sent, and the user is prompted with the download box for the file (they are even kept on the same form). However, it seems like this breaks the "Sender's message was sent successfully" confirmation box (it never appears).
If I enter the form with missing required values, no download box appears (which is great!) and the "error" confirmation box appears as expected.
This is not a huge issue for me, but I felt like I should bring it up since I'm not sure if the problem is with my code or a larger issue with the way the javascript action hook is handled.