You will need the downloaded version to force the form in the FORMS mode but you cannot attach the explanation to an efiled return ... so again if you insist of filing a form then fill it in manually, print, ink sign and mail it in by itself ... it is a stand alone form for a reason. But again, none of my clients have ever gotten an IRS letter on this matter and we skipped the 5329 completely if they had made the proper correction for future distributions AND this was their first missed payment. We took the position that if the IRS was to ever question it the client would plead stupidity for the waiver of the penalty.
