I agree that you should not complete a form 3115 manually in TT.
Form 8453 allows you to send in the form separately from a return that has been efiled. Make sure you check the appropriate box.
I'm sure this happens frequently, however, in this day and age of the IRS lack of employees (25% reduction in workforce), who knows how this works anymore.
If you do send it in separate, with form 8453, send it certified mail so you have proof of mailing.
Otherwise, send everything together (paper file) as noted by @M-MTax
Also make sure your paper copy of the filed return is sent certified as well.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
