Tim Hoffmann - 2013-11-12

Sorry, but as you may imaginge integration of external editors is not a priority in the project. The Option you are looking for is

Options -> Advanced Editor -> Special Options -> Silently Reload Files on External Changes

See also this request for details on the problem of reloading files:
https://sourceforge.net/p/texstudio/feature-requests/296/

Not sure if it is any help for you: The problem would not occur if it was possible to change the renaming of the original file to a 'save copy' operation and then overwrite the original file. That way it would not disappear in between. Since one can do everything with emacs it might be possible to configure that :).